DIYARBAKIR, Turkey (Reuters) - A man and a 15-year-old boy were killed by stray bullets shot from Syria into a Turkish border town, officials said on Wednesday. Turkish troops returned fire, in the most serious spillover of violence in weeks.
The Turkish military said it acted in accordance with its rules of engagement after bullets fired from the adjacent Syrian town of Ras al-Ain hit police headquarters in the south-eastern Turkish town of Ceylanpinar and houses in the town's centre.
The incident, which took place on Tuesday, underscores growing concern that Syria's more than two-year-old civil war is dragging in neighbouring states.
Kurdish fighters have been battling Islamist rebels in Ras al-Ain since Tuesday. Ceylanpinar is only metres (yards) across the frontier.
The boy underwent surgery after being hit in the head by a bullet, but died of his wounds on Wednesday. Security sources said clashes were still ongoing.
A local government official was lightly wounded by one bullet, the Turkish military said, but made no mention of any other casualties and gave no further details of any targets it had struck inside Syria.
Turkish troops have stepped up return fire into Syria in recent weeks due to what officials have said was heightened tension along the border and increased activity by smugglers, many of them armed.
The Syrian Observatory for Human Rights, a group opposed to Syrian President Bashar al-Assad, said Kurdish armed men had taken control of most of Ras al-Ain from Islamist rebel fighters from the al Qaeda-linked Nusra Front.
The clashes between Kurdish fighters, who generally support the creation of an autonomous region within Syria, and Islamist Arabs started on Tuesday after Nusra fighters attacked a Kurdish patrol and took a gunman hostage, the Observatory said.
Clashes between Kurds affiliated with the Democratic Union Party (PYD), a Syrian Kurdish party with links to Kurdish militants in Turkey, and anti-Assad Syrian and foreign fighters have erupted since Kurds began asserting control over parts of the northeast from late last year.
With its own large Kurdish minority, Turkey has been watching closely, worried the emergence of an autonomous Kurdish region in Syria could further embolden militants of the Kurdistan Workers Party (PKK) fighting for autonomy in Turkey.
The PKK called a ceasefire earlier this year but a recent increase in militant activity in south-eastern Turkey is fuelling fears that a peace process with Ankara could unravel. Kurdish politicians in Turkey have expressed concern the government has not been enacting reforms to fulfil its side of the bargain.
On Wednesday, Turkey's main pro-Kurdish Peace and Democracy Party (BDP) issued a statement expressing concern over what it called Ankara's support for Nusra and other affiliated groups, and said such support was leading to instability in the region and was contrary to peace efforts with the PKK.
Turkey has emerged as one of the strongest backers of the Syrian rebels fighting to overthrow Assad, giving them shelter on its soil, but denies arming them. However, like its allies, Ankara has tried to distance itself from groups like Nusra.
Ras al-Ain, also known by its Kurdish name Serekani, and Ceylanpinar were once a single town under the Ottoman Empire before they were split after World War One, and both have Arab and Kurdish communities.
In the worst example of the spillover of violence into Turkey, 52 people were killed when twin car bombs ripped through Reyhanli, another border town, on May 11. Turkey accused Syria of involvement in the attacks but Damascus has denied any role.
Turkey, which is sheltering around 500,000 Syrian refugees, has become one of Assad's most vocal critics and has scrambled war planes along the border as stray gunfire and shelling hit its soil.
Additional reporting and writing by Jonathon Burch; Editing by Nick Tattersall and Robin Pomeroy