The US consulate in Istanbul came under gunfire on Monday and at least eight people were killed in a wave of separate attacks on Turkish security forces, weeks after Ankara launched a crackdown on Islamic State, Kurdish and far-left militants.
The NATO member has been in a heightened state of alert since starting its "synchronised war on terror" last month, which has included air strikes against Islamic State fighters in Syria and Kurdistan Workers Party (PKK) militants in northern Iraq. It has also rounded up hundreds of suspected militants at home.
Police armed with automatic rifles cordoned off streets around the US consulate in the Sariyer district on the European side of Istanbul, following the gun attack there.
Local media reports said two attackers, a man and a woman, fled after police fired back. There were no immediate reports of civilian injuries. Broadcaster NTV said police later detained the female suspect, who was wounded in the gunfire.
The Dogan news agency said the woman was aged 51 and had served prison time for being a suspected member of the far-leftist Revolutionary People's Liberation Army-Front (DHKP-C), which is virulently anti-American and is listed as a terrorist organisation by the United States and Turkey.
Reuters could not immediately verify the report.
"We are working with Turkish authorities to investigate the incident. The Consulate General remains closed to the public until further notice," a consulate official said.
On the other side of Istanbul, a vehicle laden with explosives was used in an attack on a police station, injuring three police officers and seven civilians, police said.
Broadcaster CNN Turk said two gunmen and an officer from the police bomb squad, who was sent to investigate, were later killed in a firefight. Shooting continued into Monday morning in the Sultanbeyli district on the Asian side of the Bosphorus waterway, which divides Istanbul, as police carried out raids.
There was no immediate claim of responsibility for either of the attacks, but US diplomatic missions and police stations have been targeted by far-left groups in Turkey in the past.
The DHKP-C, whose members are among those detained in recent weeks, claimed responsibility for a suicide bombing at the US embassy in Ankara in 2013 which killed a Turkish security guard.
VIOLENCE IN SOUTHEAST
Violence between the security forces and suspected militants also intensified in the mainly Kurdish southeast.
Four police officers were killed when their armoured vehicle was hit by a roadside blast in the town of Silopi in the province of Sirnak, security sources said.
A soldier was also killed when Kurdish militants opened fire on a military helicopter in a separate attack in Sirnak, the military said in a statement. Security sources said at least seven other soldiers were wounded in the attack, which came as the helicopter took off.
The military launched an air campaign against PKK camps in northern Iraq on July 24 after a resurgence of militant attacks. State-run Anadolu news agency said on Sunday that more than 260 militants had been killed, including senior PKK figures, and more than 400 wounded by Aug. 1.
The violence has left a peace process with the PKK, begun by President Tayyip Erdogan in 2012, in tatters. Erdogan said last month the process had become impossible, although neither side has so far declared the negotiations definitively over.
The PKK, designated a terrorist group by Ankara, the United States and European Union, launched its insurgency in 1984 to press for greater Kurdish rights. More than 40,000 people have been killed in the conflict.