Armed men opened fire in front of the entrance to the US consulate in Istanbul on Wednesday, killing three policemen. Three attackers also died in the gunfight.
Turkish broadcaster CNN Turk later quoted police sources saying the three gunmen from east Turkey were suspected of being members of al Qaeda. It also said two people were later detained in Istanbul, one of them a brother of one of the dead assailants.
The attackers arrived around 10:30 am in a white van; stopping at the US consulate's main gate. According to eyewitnesses who talked to FRANCE 24's Istanbul correspondent Assia Shahib, "armed men got out and opened fire on the police station".
Also in Istanbul, GRN correspondent for FRANCE 24 Matt Mossman added that one of the attackers escaped in a white Renault van while another shot himself before the police could arrest him, according to eyewitnesses.
Police are searching the area. The Istinye borough, on the European shore of the Bosporus, was cordoned off. After attacks against the British consulate in Istanbul left 50 dead in 2003, the US had moved its consulate from the city centre to the high-security area.
No immediate claim for responsibility
"It was turned into a bunker to avoid this type of attack", FRANCE 24 international politics analyst Léa Salamé says.
She added that the suicide dimension of the attack could hint at connections with al Qaeda.
Turkey is a member of NATO and a close ally of the US.
No organisation has claimed the attack so far but US ambassador to Turkey Ross Wilson says the deadly attack is "an obvious act of terrorism" aimed at the United States.
Several leads may be considered, including that of the Kurdish independence party PKK whose militants are involved in regular fighting with the Turkish military on the Iraqi border.
Three German tourists kidnapped
Meanwhile, three German tourists who were mountaineering in Eastern Turkey have been kidnapped.
According to the Turkish local authorities, Kurdistan Workers Party (PKK) militants have seized the three, who were party of a 13-member team, in Agri province.