Attackers used a mobile phone to detonate the car bomb at Jakarta's Marriott Hotel, the same method used by Al Qaeda-linked bombers on the tourist island of Bali (search) last fall, police said Wednesday.

Other similarities, including the use of the same types of explosives in both attacks, could connect the regional terror group Jemaah Islamiyah to the blast Tuesday that killed up to 14 people, authorities said.

Jemaah Islamiyah (searchalmost certainly carried out the bombing, a U.S. official in Washington said on condition of anonymity. The official said the blast had the hallmarks of previous attacks by the group, an Islamic movement that officials have linked to Al Qaeda (searchand blamed for the Bali bloodshed.

Officials warned more attacks were possible in the wake of the Marriott bombing, which also wounded nearly 150. Worries about the threat of terrorism have been high in the Southeast Asian archipelago, the world's most populous Muslim nation.

Indonesian police also revealed that documents seized last month, during the arrest of seven alleged Jemaah Islamiyah members, indicated terrorists were planning to target the area around the Marriott. They said security forces had increased patrols in the neighborhood.

"There was a warning that there were some targets and we have been anticipating an attack," said police spokesman Prasetyo, who like many Indonesians uses a single name.

Two of the alleged Bali bombers expressed happiness at the attack.

"Thank God. I am thankful," Imam Samudra, the alleged mastermind of the Bali bombings that killed 202 people Oct. 12, shouted after he testified in Bali during another suspect's trial. "I am happy, especially if the perpetrators were Muslims."

One of his alleged accomplices, Amrozi bin Nurhasyim, grinned and yelled "Bomb! when asked about the Marriott attack, which came two days before a verdict in Amrozi's own trial.

President Bush telephoned Indonesian President Megawati Sukarnoputri (searchto offer condolences.

"The president emphasized that the United States stands with the people of Indonesia in their fight against terrorism, and he offered any and all assistance in bringing those responsible for the terrorist attack to justice," spokesman Scott McClellan said in Crawford, Texas.

Indonesia's chief of detectives, Erwin Mappaseng, said at a news conference that the Marriott bombers used a mobile phone to detonate the explosives, the same technique as in the Bali bombings. He said the phone was found in the wreckage.

Also like the perpetrators of the Bali bombers, the Marriott attackers used both TNT and RDX explosives, he said.

The national police chief, Gen. Da'i Bachtiar, said the Marriott bombers tried to sand down the serial numbers on the vehicle's engine and chassis, just as was done in Bali. Police were still able to retrieve all the numbers, he said.

Mappaseng said it was too early to conclude the similarities provided a definitive link between the Marriott and the Bali attacks. But Bachtiar said those facts were leading police to focus the investigation on Jemaah Islamiyah.

Mappaseng said officers had found a badly burned head close to wreckage of the bomb vehicle. "We strongly suspect that (this person) is linked with the bomb," he said.

Police also found two dismembered hands that could provide fingerprints of the suspected suicide bomber, Bachtiar said.

On Thursday, police analyzed blood and DNA samples from body parts found inside a van to identify the driver.

National police spokesman Lt. Col. Zainuri Lubis denied a media report that officers already knew the driver's identity.

"I can only confirm that we are trying to analyze DNA and blood samples found inside the vehicle," he said.

The Straits Times in Singapore reported Wednesday that it had received a phone call from a Jemaah Islamiyah operative claiming responsibility for the Marriott bombing. The caller said the attack was a response to the Indonesian government's crackdown on Islamic militants.

The newspaper's correspondent in Jakarta, Derwin Pereira, said he arranged to speak to the purported operative through a "well-placed" informant who had warned two weeks ago of an impending attack in Indonesia.

Health Minister Achmad Suyudi said Wednesday that 10 people were confirmed killed in the bombing and 147 people were wounded. The Indonesian Red Cross had said 14 people were killed but retracted that.

The Marriott, which faces a traffic circle that by Jakarta standards has light traffic, is about 150 feet from the street and has no gates at the entrance.

The suspected car bomb went off near the hotel's front entrance beside an adjacent office building -- probably around the point where security guards normally check vehicles entering and leaving.

Police released a composite sketch of one of two men who reportedly purchased the vehicle used in the bombing.

Indonesia's economy is still reeling from the effects of the Bali bombings. It had recently been showing signs of bouncing back, but Indonesians worried Tuesday's attack would bring another falloff in foreign investment and tourism.

Indonesia's top security minister, Susilo Bambang Yudhoyono, warned of more terrorist attacks, saying the trials of Jemaah Islamiyah members were reason enough for Muslim extremists to lash out.

Australian Foreign Minister Alexander Downer said his government had acquired intelligence in the hours after the bombing that there could be more terrorist attacks in Indonesia in the coming days. He did not say what the intelligence was.

Indonesia's largest Muslim groups, Nahdlatul Ulama and Muhammadiyah, released a joint statement condemning the bombing.

"The attack on the Marriott constituted a cruel and uncivilized crime against humanity, and ran against religious values," the groups said.