Turkish investigators arrested suspects Friday in the deadly suicide bombings of the British consulate and a London-based bank that were blamed on Al Qaeda. The United States and other countries, meanwhile, warned that terrorists could target Turkey with more attacks.

Foreign Minister Abdullah Gul (search) confirmed the arrests of an undisclosed number of suspects in Thursday's bombing, but declined to elaborate.

"Some people have been arrested, but its too early to give information about them," he said.

The daily newspaper Hurriyet said police were interrogating seven people in connection with the attack, which killed 27 people and the two bombers in Turkey's deadliest terrorist blast. The attacks came days after bombings at two Istanbul synagogues killed 23 people.

According to the Hurriyet report, police believe they have identified the suicide bombers as two Turkish men previously named as accomplices of the synagogue bombers. Istanbul Gov. Muammer Guler refused to give details of those arrested "for the well-being of the investigations."

Turkey's top political and military leaders met to discuss intelligence reports that local Islamic militant groups and Al Qaeda have been collaborating, an official said, speaking on customary condition of anonymity. The top leaders hold regular monthly meetings focused on issues of national importance.

Turkey's National Security Council issued a statement afterward that said the attacks showed a need for "intensifying regional and global cooperation" to fight terrorism.

In a BBC interview, former Prime Minister Tansu Ciller (search) said Al Qaeda likely was involved in the attacks "but they also have some contacts with the terrorists that are already in Turkey."

Turkish security forces were on high alert. Security was tightened at public buildings and foreign institutions, and Istanbul police were stopping and searching pickup trucks similar to those that shattered the British consulate and the HSBC bank building. British anti-terrorist experts headed to Turkey to help the investigation.

Prime Minister Recep Tayyip Erdogan (search) vowed to defeat the attackers, who struck during the Islamic holy month of Ramadan.

"Those who bloodied this holy day and massacred innocent people will account for it in both worlds," he said Thursday. "They will be damned until eternity."

At least three groups or individuals allegedly linked to Al Qaeda claimed responsibility for the attacks.

One called the Abu Hafs al-Masri Brigades posted a Web site statement saying it struck "to let Britain and the Brits know that their alliance with America will only bring them economic ruin and death to their sons."

The statement claimed to have deliberately targeted British Consul-General Roger Short, who was killed along with his personal assistant, Lisa Hallworth. The group called Short the "mastermind of the British policy in Iraq, Turkey, Syria, and Iran because of his extensive experience in ... combating Islam."

U.S. officials have cast doubt about previous claims by Abu Hafs al-Masri, saying there is no proof the group exists or has links to Al Qaeda.

On Thursday, an unidentified caller to the semiofficial Anatolia news agency said Al Qaeda and a small militant Turkish group, the Islamic Great Eastern Raiders' Front, or IBDA-C, jointly claimed responsibility for both sets of attacks.

The same groups earlier claimed responsibility for Saturday's synagogue bombings.

Another claim came from an alleged Al Qaeda operative, Abu Mohammed al-Ablaj, in a statement to the London-based Al-Majalla weekly.

He warned of a "big operation" somewhere between the Muslim holidays of Eid el Fitr next week and the Feast of the Sacrifice in January. His e-mail also warned Japan against helping the United States in Iraq, saying Tokyo "is the easiest place to destroy."

In Washington, Attorney General John Ashcroft said the attacks bore the marks of an Al Qaeda operation. Saturday's synagogue attacks were also blamed on Al Qaeda.

The U.N. Security Council unanimously passed a resolution urging all states to cooperate to track down the perpetrators.

The attacks raised fears Al Qaeda was targeting Turkey, a close ally of the West that has strong ties with Israel and is a rare example of a secular, Muslim democracy.

Istanbul may have been hit "because Turkey is a successful democracy" said British Foreign Secretary Jack Straw, who rushed to Istanbul following Thursday's attack.

Straw said the decision to warn citizens against nonessential travel to major Turkish cities was based on intelligence reports of more threats.

Other nations, including the United States, Germany and Australia, issued similar warnings — prompting fears that drops in foreign investment and tourism could harm the country's recovery from its worst recession in decades. The Istanbul stock exchange remained closed Friday after plummeting 7 percent before shutting early after the bombings.

To boost the economy, Straw said Britain would intensify its backing for Turkey's long-standing bid to join the European Union. HSBC bank, the world's second largest financial institution, opened its 162 branches around Turkey on Friday despite the destruction at its Istanbul headquarters.

The bombings against British targets coincided with President Bush's visit to London.

As with the synagogue bombings, most victims were Muslim Turks. At least 450 people were injured, said Interior Minister Abdulkadir Aksu. British officials said up to four of the dead were British. One Turkish woman was reported brain dead Friday.

Hurriyet quoted police sources as tentatively identifying the two bombers in Thursday's attack as Turkish men: Azad Ekinci and Feridun Ugurlu. Earlier reports linked the two to the synagogue bombings.

Hurriyet said Ekinci and Ugurlu traveled to Dubai in the United Arab Emirates on Oct. 28, a report questioned by authorities in the Gulf nation. The paper identified Ekinci as a schoolmate of one suspect in the synagogue attacks. Earlier reports said Ekinci had also traveled to Iran, received military and explosive training in Pakistan between 1997-99 and fought in the Chechnya.

Witnesses said one pickup truck exploded in front of the HSBC bank building, devastating its 18-story facade. The second crashed through the gate of the British consulate destroying annexes to the main building.

Hurriyet reported that police in front of the consulate opened fire as the men approached the consulate, but failed to stop them from detonating the explosives. Two of the dead where policemen.

Authorities arrested six people Wednesday in the synagogue bombings. The two suicide bombers who attacked the synagogues were identified as Turks who Gul said had visited Afghanistan.