America's NATO ally Turkey is fighting US-backed Kurdish forces in northern Syria in the wake of mixed messages sent by the US amid the fight against the Islamic State.
The attack is indicative of the complicated situation in Syria, where NATO member Turkey is allied with the US against Islamic State, while the US also supports the Kurds, who support a Kurdish insurgency in Turkey.
The Turkish forces are part of a coalition that includes Syrian rebels and American aircraft aimed at pushing ISIS from the Syrian border town of Jarablus.
Three soldiers were killed and six others were wounded when a bomb hit a military vehicle in southeastern Turkey on Thursday, the latest incident of bloodshed.
One official with the Kurdish militia known as the PKK believes the children are no longer in Iraq, and that their father may have taken them across the border into Iran.
The fourth suicide attack in Turkey this year hit Istiklal Street, a wide shopping boulevard in Istanbul that is lined with international stores and shopping centers.
The Turkish government had earlier blamed the PKK for the attack. Ankara has now been hit by three bombings in a space of five months, ratcheting up security fears across the city and Turkey.
The Kurds have asserted de-facto control of a large swath of northern Syria amid the civil war — now they are poised to formally declare their own federal system.
The PKK has historically struck directly at the security forces and says it does not target civilians. A direct claim of responsibility for Sunday's bombing would indicate a major tactical shift.
Activists from across the UK took to the streets on Sunday to protest against the ongoing conflict between the Turkish military and the Kurdish PKK militants.
The two female attackers were killed by officers after they fired shots and threw a grenade at a police bus. Meanwhile, three soldiers and 10 Kurdish militants have been killed in southeast Turkey.
The deadly bombing in Ankara was carried out by Syrian Kurdish militia with help from the PKK, Turkey said, as another bomb exploded in the southeast of the country.
The Turkish army shelled Kurdish militia in northern Syria for a second day on Sunday, while Russia made clear it would continue bombing Syrian rebel targets, raising doubts that a planned ceasefire would bring much relief.
Hundreds have fled their homes amid violence still raging in Turkey's southeast. In another city, six people out of a group trapped in a basement for nearly two weeks are reported to have died.
A new report accuses the Kurds of sectarian violence, while an intelligence assessment says Ottawa should vet whether its citizens are fighting with the PKK.
