Police detained four suspects and patrolled the high-walled perimeter of the U.S. consulate in Istanbul on Thursday after 3 policemen and 3 gunmen were killed in what a minister said was a suicide attack.
Busloads of police were stationed outside the mission, where the U.S. flag flew at half-mast. Security was tightened at other diplomatic installations and police manned checkpoints across the sprawling city to check the identity of passing motorists.
The attack coincides with political tension in Turkey.
The governing party is fighting to avoid being banned for alleged anti-secular activities and police are investigating a shadowy far-right group suspected of plotting a military coup.
Interior Minister Besir Atalay said police had obtained more information on the consulate attack from the four suspects and were taking it seriously. Three of them were seized in Istanbul.
He said more people may be detained, state-run Anatolian news agency reported. Police were still seeking a fourth person at the scene who escaped during the gunbattle.
"The general view is that this was a suicide attack," Atalay told reporters at Istanbul police headquarters after an official funeral ceremony for the three dead officers.
Turkish police were investigating whether al Qaeda was behind Wednesday's attacks. Newspapers reported that the gunmen who carried it out had received weapons training in Afghanistan.
Atalay said only one gunman seemed to have travelled abroad.
There was scepticism among some security experts that al Qaeda was behind the assault on the consulate, given the small scale and amateurish nature of the attack.
DEAD POLICE MOURNED
At the official funeral ceremony at police headquarters in Istanbul, lines of police and officials said prayers in front of the three officers' coffins, draped in Turkish flags.
"We saw once more that terror is ruthless, has no religion, faith or nationality. We condemn terrorism from wherever it comes. We will continue the fight against terrorism to the end," Atalay said.
Turkey has seen violent attacks from a variety of groups over the years, including far-left, Kurdish and Islamist militants.
The most serious were in November, 2003, when 62 people were killed by Islamists who struck at two synagogues, a bank and the British consulate in Istanbul.
The U.S. consulate had already been moved to a more secure location in Istanbul following the September 11, 2001 al Qaeda attacks in New York.
A father of one of the gunmen had spent three months in prison after being detained as part of an investigation into the Turkish Islamist militant group Hizbullah, broadcaster CNN Turk said.
The three gunmen had lived in the same Istanbul district and one of them had recently completed his military service.
In Turkey's eastern Igdir province, friends and relatives of one of the dead gunmen, named as Bulent Cinar, expressed shock at his involvement, Anatolian said.
"Bulent was a good boy. We were shocked when we heard what happened. I can't understand how he could do such a thing. He was definitely deceived," said Erhan Karaboga, a friend of his.
