Calling Amman the "backyard garden for the enemies of the religion," Al Qaeda in Iraq claimed responsibility for three homicide bomb attacks on Western hotels in the Jordanian capital that killed at least 56 people and injured at least 115 others.

That death toll does not include the three dead bombers themselves. At least one American was among those killed, according to a U.S. Embassy official, while two others were wounded.

The Al Qaeda claim, posted on a militant Internet site, said Jordan became a target because it was a haven for "Jews and crusaders ... a filthy place for the traitors ... and a center for prostitution."

It also linked the attacks to the war in Iraq.

One of the bombers spoke with an Iraqi accent, a top security official said. The middle-aged man was stopped by suspicious Grand Hyatt hotel security before detonating explosives hidden under his suit, the official said.

Authorities also reported arresting a number of Iraqis as security forces scrambled to capture anyone behind the attacks at the Grand Hyatt, Radisson SAS and Days Inn hotels before they could flee the country.

The authenticity of the posting could not be independently verified, but it appeared on an Islamic Web site that acts as a clearing house for statements by militant groups.

The claim of responsibility, signed in the name of the spokesman for Al Qaeda in Iraq, said the attacks put the United States on notice that the "backyard camp for the crusader army is now in the range of fire of the holy warriors."

The attacks have caused a great deal of anger in Jordan aimed at Al Qaeda in Iraq and its leader, Jordanian-born Abu Musab al-Zarqawi.

Jordanians on Thursday were holding anti-Zarqawi demonstrations in the street in support of their king. Some were chanting: "Abu Musab al-Zarqawi — burn in hell."

About 50 Jordanians, including children carrying small flags, placed burning candles on a sand memorial in the driveway of the Grand Hyatt as darkness fell.

The Amman protest was organized by Jordan's 14 professional and trade unions — made up of both hard-line Islamic groups and leftist political organizations — traditionally vocal critics of King Abdullah II's moderate and pro-Western policies.

Protesters — including women and children — gathered outside a bombed hotels, shouting, "Death to al-Zarqawi, the villain and the traitor!" Drivers honked the horns of vehicles decorated with Jordanian flags and posters of the king. A helicopter hovered overhead.

"We sacrifice our lives for you, Amman!" the protesters chanted.

State television said a second rally was planned in the Red Sea port of Aqaba, where attackers using Katyusha rockets narrowly missed a U.S. ship and killed a Jordanian soldier in August. Others were in al-Zarqawi's hometown of Zarqa and the southern city of Maan, which is a known hub for Muslim fundamentalists.

The streets of the capital appeared deserted early Thursday, which was declared a day of mourning. Public and private offices were closed under government instructions, apparently to allow tightened security measures to take hold.

Abdullah vowed that such "criminal" acts "would not dissuade Jordan from pursuing its role in fighting terrorism and the criminal terrorist groups and those who are behind them and justify their acts" and vowed that the terrorists will be brought to justice.

President Bush called Abdullah on Thursday to express the United States' condolences and told the king that he strongly supports his leadership and that the United States will stand with Jordan.

"The bombings should remind all of us that there's an enemy in this world willing to kill innocent people, willing to bomb a wedding celebration in order to advance their cause," Bush said during a photo op with the president of Yemen. "For those of us who love freedom, for those of us who respect every human life … we have an obligation and a duty to remain strong, to remain firm and to bring these people to justice."

Investigation Continues

Police continued a broad security lockdown and authorities sent DNA samples for testing to identify the attackers. Land borders were reopened after being closed for nearly 12 hours.

A security official in Amman said authorities had tips on suspects who are being hunted, including possible sleeper cells or individuals who may have assisted the attackers and later fled in a vehicle bearing Iraqi license plates.

Police detained several people, although it was unclear if they were suspects or witnesses.

"They are being interrogated as we speak," police spokesman Maj. Bashir al-Da'aja told the AP.

The official said that DNA tests were being carried out to determine the identity of the perpetrators, including two homicide bombers who blew themselves up in two of the separate hotel attacks. It was originally thought the third attacker used a car but now it's believed that the bomber at the Days Inn tried to detonate himself inside the hotel lobby, but his bomb did not go off until he rushed outside the hotel lobby.

One U.S. counterterrorism official told FOX News that all three bombers walked into the hotels or the hotel area; wearing explosive vests laden with ball bearings. The official Petra news agency quoted doctors who treated the injured as saying many wounds were inflicted by ball bearings used in the bombs.

Government spokesman Bassel Tarawneh said the victims included 15 Jordanians, five Iraqis, one Saudi, one Palestinian, three Chinese and one Indonesian; 30 others hadn't been identified.

Iraqi government spokesman Laith Kubba said the attack should alert Jordan that it needed to stop playing host to former members of Saddam Hussein's regime.

"I hope that these attacks will wake up the 'Jordanian street' to end their sympathy with Saddam's remnants ... who exploit the freedom in this country to have a safe shelter to plot their criminal acts against Iraqis."

He also said Iraqis may have had a hand in the attacks.

"The Al Qaeda organization has become as a plague that affected Iraq and is now transmitted by the same rats to other countries. A lot of Iraqis, especially former intelligence and army officers, joined this criminal cell," Kubba said.

Jordan's Deputy Prime Minister Marwan Muasher said shortly after the blasts that al-Zarqawi was a "prime suspect."

The Jordanian-born al-Zarqawi is known for his animosity to the country's Hashemite monarchy. The claim of responsibility did not name King Abdullah II but twice referred to the "tyrant of Jordan."

Wedding Celebration Horror

The homicide bombers detonated explosives Wednesday at the Grand Hyatt, Radisson SAS and Days Inn hotels.

The first blast was reported at about 8:50 p.m. at the five-star Grand Hyatt. Video supports witness claims that the bomber blew up in an open area in the hotel lobby near the piano bar. The force of the blast literally knocked people out of their shoes.

Thousands of shards of broken glass crunched underfoot as hotel bellboys, some bloodied by the blast, ran alongside luggage trolleys being used to transport the wounded.

An American man blurted out in a thick Southern drawl: "My friends are dead."

Steve Olderman, a businessman from England, was attending a business dinner at the Grand Hyatt, where an information technology conference took place earlier in the day.

"Suddenly, we heard an explosion and the whole hotel filled with smoke, and suddenly we found ourselves outside the hotel," said Olderman, who was on the ground floor at the time of the attack.

"We saw bodies lying as we were coming out" of the hotel, said Olderman, who had been staying at the Radisson. "It was pretty horrific. We were sitting beside a huge plate glass window and it just exploded beside us. ... We were lucky to get out alive."

Then, just before 9 p.m. local time, as a new married couple was entering the ballroom of the Radisson SAS to greet their guests, a man strapped with explosives who had infiltrated the crowd blew himself up.

Ibrahim Akhras, the groom's cousin, said he had left the hotel to buy flowers and was just returning when the blast went off.

"I found huge devastation in the hall. I saw bodies and blood. The ceiling of the hall collapsed over the people, and I saw kids and women screaming in their blood," he said.

"No religion, no Islam, no Muslim people allow this to happen."

A doctor staying at the hotel said smoke was seen coming out of the wounds of people lying on the ground.

The groom, Ashraf al-Akhras, who suffered serious injuries, said both his father and his wife's father were among the dead.

In the West Bank village of Silet al-Thaher, the Akhras clan set up a house of mourning, and 35-year-old Najah Akhras, who lost two young nieces, cried and shouted: "Oh my God, oh my God! Is it possible that Arabs are killing Arabs, Muslims killing Muslims? For what did they do that?"

The Radisson is popular with American and Israeli tourists and was a target of several foiled Al Qaeda plots, including a conspiracy to attack U.S. and Israeli tourists during the kingdom's millennium celebrations. No Israeli casualties were reported.

The third explosion was at the Days Inn. Early reports said a car bomb was used, but later reports indicated the bomber had walked into the hotel but had to come back out to detonate his explosives. The casualties at the Days Inn were not so extensive as at the other hotels.

The Palestinian envoy to Amman said the victims included two high-ranking Palestinian security officials, a senior Palestinian banker and the commercial attache at the Palestinian Embassy in Cairo, Egypt.

Maj.-Gen. Bashir Nafeh, the head of military intelligence in the West Bank, and Col. Abed Allun, a high-ranking Preventive Security forces official, were killed in the attack at the Grand Hyatt Hotel, Ambassador Attala Kheri told The Associated Press.

An east Jerusalem businessman, Bashar Qadoumi, also was killed, his family said.

Three Chinese were killed, all from the Defense University of the Chinese People's Liberation Army — an elite military training university, the Foreign Ministry in Beijing said Thursday.

Chinese President Hu Jintao "strongly condemned" the attack and reiterated that his government firmly opposes terrorism in all its forms, in a telegram to Jordan's King Abdullah II, the ministry said.

In addition to housing Westerners, Amman's hotels have become a gathering spot for affluent Iraqis who have fled their country's violence. Their presence — and money — has caused an economic boom and attracted high-priced prostitutes.

Until late Wednesday, Amman — a comfortable, hilly city of white stone villas and glitzy high-rises — had mostly avoided large-scale attacks and was a welcome sanctuary of stability in a troubled region.

"Obviously this is something Jordan is not used to," Muasher said. "We have been lucky so far in avoiding those incidents."

Al-Zarqawi is most known for the string of devastating homicide attacks launched in Iraq, often against U.S. targets but also against Shiite Iraqis. He has shown a flair for propaganda and drawn wide support among militants in the region.

The terror leader was sentenced to death in absentia by a Jordanian military court for the October 2002 assassination of a U.S. diplomat, Laurence Foley, in Amman.

Al-Zarqasi's group also is accused of previously trying to blow up the Radisson SAS in Amman as part of the so-called Millennium plot in 1999 and of an attack this August on a U.S. Navy ship in the Jordanian port of Aqaba that killed one Jordanian soldier.

The state Jordan Television showed Abdullah inspecting the sites of the blasts after returning home early Thursday, cutting short an official visit to Kazakhstan. He later presided over a meeting of his security chiefs, including police and intelligence.

The date of Wednesday's attack, Nov. 9, would be written as 9/11 in the Middle East, which puts the day before the month. A Jordanian government spokesman declined to speculate on what this means. But Jordanian citizens were sending mobile messages that read: "Have you noticed that today is 9-11, similar to America's 11-9?"

FOX News' Catherine Herridge and Mike Tobin and The Associated Press contributed to this report.