By Jonathon Burch
ANKARA (Reuters) - A Syrian Kurdish party with links to Kurdish militants in Turkey has seized control of a Syrian town on the Turkish border after days of clashes with Islamist fighters, the Turkish military said.
The capture of Ras al-Ain by the Democratic Union Party (PYD) will heighten Ankara's fears the emergence of an autonomous Kurdish region in Syria could embolden homegrown militants of the Kurdistan Workers Party (PKK), which is fighting for autonomy in Turkey.
Turkey's foreign minister voiced concern at the spillover of violence from the war in its southern neighbor and called again on the United Nations Security Council, which has yet to come to a consensus over Syria, to act.
In a statement late on Wednesday, the military said the northeastern Syrian town of Ras al-Ain had fallen under the control of the PYD, which it described as a "separatist terrorist organization". Fighting in the town had stopped, it said.
Turkish troops had shot at PYD fighters in Syria in accordance with their rules of engagement, after two rocket-propelled grenades fired from Syria struck a border post on the Turkish side of the frontier.
The return fire was the second time in as many days the military had answered in kind. Stray bullets from Syria struck the police headquarters and several homes in the adjacent Turkish town of Ceylanpinar on Tuesday.
A Turkish citizen was killed and a 15-year-old boy seriously wounded by the stray fire, in the most serious spillover of violence into Turkey from Syria in weeks. Earlier officials said the boy had died of his wounds but later said he was still in a critical condition and had been moved to Ankara.
The military said it had strengthened security along that part of the border with armored vehicles.
The clashes between Kurdish fighters, who want an autonomous region within Syria, and Islamist Arab fighters from the al Qaeda-linked Nusra Front started on Tuesday after Nusra fighters attacked a Kurdish patrol, according to an anti-government Syrian activist group.
Clashes between Kurds affiliated with the PYD, and Syrian and foreign fighters opposed to Syrian President Bashar al-Assad, have erupted since Kurds began asserting control over parts of the northeast from late last year.
Turkey, with its own large Kurdish minority, has been watching closely, concerned a Kurdish power grab to the south could strengthen PKK militants in Turkey with whom Ankara has embarked on a peace process.
Developments in Syria could threaten that process, which is already under pressure amid an increase in militant activity in Turkey.
Turkey's main pro-Kurdish party, the BDP, on Wednesday criticized Ankara's Syria policy and said it worked against peace efforts with Turkey's Kurds.
Nihat Ali Ozcan, an expert on the PKK and security at the Economic Policy Research Foundation of Turkey (TEPAV) think-tank, said the events in Syria would likely embolden the PKK.
"Firstly, there will be a psychological effect, and as the PKK watches these developments they will make more maximalist demands from the government. They will sit down to negotiations with the government as a much stronger actor," Ozcan said.
"The PKK has gained an important resource in the area, it has gained depth and will also make economic gains. This is good news for the PKK," he said.
Speaking in Ankara on Wednesday, Foreign Minister Ahmet Davutoglu expressed concern over the events along the border.
"This illustrates a striking picture of how much the crisis in Syria can affect us and our citizens," state-run broadcaster TRT quoted Davutoglu as saying.
"Once again we call upon the international community ... if the U.N. Security Council is to do the job it is required to do, then the moment is now," he said.
Turkey, one of Assad's most vocal critics and biggest backers of the Syrian rebels, has criticized the U.N. Security Council for failing to adopt a united stance on the conflict.
Prime Minister Tayyip Erdogan was expected to meet President Abdullah Gul and the military's Chief of General Staff Necdet Ozel on Thursday and the latest developments in Syria were likely to feature high on the agenda.
Turkey, which has the second-largest army in NATO, is reluctant to act unilaterally in Syria although it has scrambled warplanes along the border as gunfire and shelling hit its soil. Turkey hosts around 500,000 Syrian refugees.
(Additional reporting by Gulsen Solaker; Writing by Jonathon Burch; Editing by Andrew Roche)