At least 27 people were killed and nearly 450 wounded Thursday as two suicide truck bombs were blasted outside the British consulate and the headquarters of the London-based HSBC bank.
A man calling the semi-official Anatolia news agency claimed that Al Qaeda and the Great Eastern Raiders' Front (search), or IBDA-C, a Turkish Islamic militant group, jointly claimed responsibility for attacks.
Among the dead was British Consul-General Roger Short (search), Fox News confirmed. Short, 58, served as consul-general in Istanbul since 2001, was Britain's ambassador to Bulgaria from 1994-98 and oversaw peace-building efforts in Bosnia-Herzegovina between 1999-2000 while heading the Office of the High Representative.
Turkish Premier Recep Tayyip Erdogan (search) vowed to defeat the terrorists. "The goal of these attacks is doomed to be destroyed in the face of the government's determination ... and international solidarity in fighting terrorism," he said.
Currently, the U.S. State Department knows of no Americans killed or hurt in the blast. British Foreign Secretary Jack Straw said three or four British employees from the consulate had not reported to roll call following the blasts.
Interior Minister Abdulkadir Aksu said homicide bombers caused the explosions. Of the injured, four were in critical condition and 15 others were undergoing surgery, Istanbul health officials said.
The bombings, which occurred five minutes apart, at about 11 a.m. local time, came five days after two synagogue bombings in the city and coincided with President Bush's visit to London.
"We see their utter contempt for innocent life. The terrorists hope to intimidate, they hope to demoralize. They are not going to succeed," Bush said at a news conference with Prime Minister Tony Blair Thursday.
Sky Turk reporter Mustafa Azizoglu told Fox News "this is not an ordinary attack," and said "this is the eleventh of September for Istanbul."
The explosions were "trying to target Western financial institutions," he added.
Straw described the attacks as "clearly appalling acts of terrorism."
"I'm afraid it has all the hallmarks of international terrorism practiced by Al Qaeda," he said.
Turkish authorities said the same groups were behind Saturday's nearly simultaneous synagogue bombings in Istanbul, which killed 23 people and the two attackers.
Turkish media reported the attacks were carried out by homicide bombers, but the governor's office said only that attackers blew up explosive-laden pickup trucks.
Marc Ginsberg, a former U.S. ambassador to Morocco, told Fox News that two domestic Islamic militant groups - the Great Eastern Raiders' Front and Turkish Hezbollah (search), or Party of God (not affiliated with Lebanese Hezbollah) - were increasing activities in Turkey.
"These are local affiliates, more or less, of the Al Qaeda network," Ginsberg said. "These organizations apparently have resurrected themselves in Turkey in recent months and these are the organizations that are doing the dirty work of Al Qaeda in Turkey."
As the holy month of Ramadan comes to a close, "Al Qaeda franchise organizations are trying to show their strength," he added.
U.S. Attorney General John Ashcroft said Thursday's attacks "appear to be in the method of operation or the operational style of Al Qaeda or Al Qaeda operatives or affiliates."
"We are deeply distressed over this assault on the liberty, live and security of individuals in Turkey," Ashcroft said. "It is quite clear that terrorism is very, very active at this moment and at this time, but it has been active since Sept. 11 … we should make no mistake that somehow terrorism is abating."
'There Must Be No Holding Back'
The first blast was at the Turkish headquarters of HSBC, the world's second-largest international bank, shearing off the façade of the 18-floor building and shattering the windows of nearby skyscrapers.
Body parts, the charred shells of cars and broken glass were scattered around a 9-foot-deep crater. Bystanders bloodied and covered in dust looked dazed. Several people helped carry the limp bodies of victims.
Another bomb ripped off the wall surrounding the garden of the British consulate in the downtown Beyoglu district.
"Once again we are reminded of the evil these terrorists pose to people everywhere and to our way of life," Blair said in London. "Once again we must affirm that in the face of this terrorism there must be no holding back, no compromise, no hesitation in confronting this menace, in attacking it wherever and whenever we can and in defeating it utterly."
Blair also reaffirmed his commitment to the U.S.-led coalition in Iraq.
"It should not lessen ... our commitment to Iraq," he said. "On the contrary, it shows how important it is to carry on until terrorism is defeated there as well."
One witness was traveling on a bus near the HSBC building when the explosion occurred.
"I thought somebody hit our bus from the back, then I saw black smoke rising. Cars were damaged all around us. I saw the charred body of a driver at the wheel," said a sobbing Mehmet Altan.
"After the blast the bus doors got stuck and passengers broke the windows to get out. There were pieces of flesh spread all around," said bus driver Necati Erkek.
Hakan Kozan, 29, who was close to the British consulate, said a white pickup truck was responsible for the blast. Mehmet Celik, who was slightly injured, said a light brown pickup truck "exploded in front of the HSBC headquarters."
Trading on the Turkish stock market was suspended. Some businesses, including the leading Yapi Kredi bank near HSBC and an IBM office near the British consulate, reportedly halted operations on Thursday after the explosions.
'A High Threat of Terrorism'
The British consulate is located in the cramped historic Beyoglu district (search), a popular tourist destination with shops, bars, movie theaters and restaurants.
The British embassy also issued a warning saying, "we advise against all but the most essential travel to Istanbul, until the situation becomes clearer."
The embassy also said that the British consulate's services would be scaled back.
"There is a high threat from terrorism in Turkey," the warning stated. "We urge you to be vigilant in all parts of the country, and especially in the vicinity of potential terrorist targets."
The nearby U.S. consulate was moved months ago to a new, more secure location in another district. It formerly was situated just a few blocks from the British consulate.
Fox News' Teri Schultz, Anna Stolley and The Associated Press contributed to this report.