Turkey was on Monday hit by a slew of deadly attacks, with six members of the security forces killed and the US consulate in Istanbul targeted in a shooting.
The violence, which authorities blamed on Kurdish and Marxist radicals, comes as Ankara presses a two-pronged "anti-terror" offensive against Islamic State (IS) jihadists and Kurdistan Workers' Party (PKK) militants following a wave of attacks in the country.
Monday's attacks raised fresh concerns about security throughout Turkey in an escalating cycle of violence that has left a 2013 ceasefire agreed by the PKK in tatters.
UN Secretary-General Ban Ki-moon and the European Union both condemned the "terrorist attacks", with Ban expressing hope that the perpetrators would be "swiftly brought to justice".
Four Turkish police officers were killed in a roadside bombing, blamed on Kurdish militants, in the southeastern Silopi district of Sirnak province bordering Iraq and Syria, the official Anatolia news agency said.
A Turkish soldier was killed in a separate incident when Kurdish militants attacked a military helicopter with rocket launchers in Sirnak's Beytussebap district, the army said.
In Istanbul, Turkey's largest city, a suspected suicide bomber blew up a vehicle packed with explosives at a police station in the Sultanbeyli district just after midnight, wounding 10 people, three of them police, the governor's office said in a statement.
Clashes with police continued throughout the night. Beyazit Ceken, head of the police bomb disposal department, was wounded in the unrest and died of his injuries in hospital, the governor's office said.
President Recep Tayyip Erdogan later joined mourners at Ceken's funeral in Istanbul broadcast live on television.
Two militants were killed in the clashes as well as the suicide bomber, the governor's office added.
- Leftist women attack US consulate -
Meanwhile, two armed women early Monday launched a gun attack against the well-fortified US consulate on the outskirts of Istanbul.
One of the women was later arrested after being wounded in clashes with police.
The outlawed Marxist Revolutionary People's Liberation Party–Front (DHKP-C) said one of its militants -- named as Hatice Asik -- had carried out the attack.
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The DHKP-C has carried out a string of attacks in Turkey in the past, claiming a 2013 suicide bombing at the US embassy in Ankara.
The authorities have targeted suspected DHKP-C, IS and PKK members in a succession of "anti-terror" raids in the last two weeks.
A consulate spokesperson confirmed that there had been a "security incident" near the mission and the building remained closed to the public until further notice.
A Turkish official in Ankara told AFP that the US consulate attack was linked to the DHKP-C and the Istanbul police station bombing by the PKK.
But the Istanbul police attack was also claimed by a smaller leftist group, the People's Defence Units (HSB), on its Twitter feed.
- 'Turkey protecting IS' -
The state-run Anatolia news agency said over the weekend that so far 390 "terrorists" have been killed in the air campaign in Turkey and northern Iraq with 400 wounded.
The PKK's insurgency for greater rights and powers for Turkey's Kurdish minority began more than 30 years ago and has left tens of thousands dead.
The PKK is designated as a terrorist organisation by Turkey, the EU and the United States but Ankara's Western allies have urged it to show restraint in the onslaught.
Senior PKK figure Cemil Bayik told the BBC in an interview Monday that Turkey was trying to protect IS by fighting the PKK, who are bitterly opposed to the jihadists.
"They are doing it to limit the PKK's fight against IS. Turkey is protecting IS," he said.
According to an AFP toll, 28 members of the security forces have been killed in violence linked to the PKK since the current crisis began.
The government has also vowed to begin strikes against IS jihadists in Syria alongside US forces who have now started arriving to use the well-located Incirlik air base in southern Turkey.
Washington has long been pushing its NATO ally Turkey to step up the fight against IS, which Ankara had been reluctant to do.
But Turkish officials have vowed that a wider fight against IS will start in the coming days.