By Orhan Coskun and Sylvia Westall
ANKARA/BEIRUT (Reuters) - Turkish forces returned fire on Islamic State militants in Syria with tank shells on Thursday after a Turkish soldier was killed and two others were wounded in a cross-border firefight, military and government officials said.
The fighting comes days after a suspected suicide bombing by the Islamist radical group in a Turkish border town killed 32 people, many of them students and some of them Kurds, touching off waves of violence in the largely Kurdish southeast.
Turkey's NATO allies have long expressed concern about control of the border with Syria, which in parts runs parallel with territory controlled by Islamic State. Monday's suicide bombing in the southeastern town of Suruc highlighted fears about the Syrian conflict spilling onto Turkish soil.
The Turkish army has stepped up security along parts of the border, as fighting in Syria involving Kurdish militia, Islamist militants and Syrian security forces intensifies.
"Turkish soldiers returned fire after shots came from the Syrian side of the border, from the region where Islamic State militants are," a Turkish official said, adding that, in line with rules of engagement, four tanks returned fire after being fired upon by the militants.
The army said one sergeant had been killed and two others wounded. One Islamic State militant had been killed, and Turkish forces had later retrieved his body and rifle.
Another Turkish official said fighter jets had been scrambled to the Syrian border, although Turkish jets regularly patrol the 900 km (560 mile) frontier with Syria.
Rami Abdulrahman, founder of the U.K.-based Syrian Observatory for Human Rights that tracks the conflict in Syria through a network of sources on the ground, gave a different account.
He said the clashes erupted when two Syrian civilians tried to cross into Turkey and the army opened fire, killing one of them, an elderly man. Islamic State then returned fire and two of their militants were killed, he said.
The Turkish army was not immediately available to comment.
Local media said the fighting was close to the village of Elbeyli, east of Kilis, and an area where the armed forces have sent reinforcements in recent weeks.
BORDER PROTECTION
The skirmish came a day after U.S. President Barack Obama and Turkish President Tayyip Erdogan agreed to work together to stem the flow of foreign fighters and secure the border.
U.S. defence officials said the United States and Turkey had reached agreement to allow U.S.-led coalition warplanes to use the Incirlik U.S. Air Force base in eastern Turkey for strikes against Islamic State. The officials, speaking on condition of anonymity, declined to disclose specifics.
The U.S. currently is not allowed to fly any bombing sorties, but does launch drones. Agreement for the use of Incirlik marks a significant Turkish move in cooperation with Washington over Syria.
The clashes were the latest in a wave of violence that followed Monday's suspected Islamic State suicide bombing.
The Suruc bombing enraged Turkey's Kurdish minority, many of whom suspect the government of tacitly backing Islamic State in Syria against Kurdish forces, something Ankara strongly denies
One police officer was shot and killed and a second wounded on Thursday in the mainly Kurdish city of Diyarbakir, security sources said. On Wednesday two police officers were killed in a town on the Syrian border and militants from the Kurdistan Workers Party (PKK) claimed responsibility.
Turkey has been negotiating an end to the PKK's 30-year-old campaign for autonomy for Turkey's estimated 14 million Kurds and is worried about its growing influence in war-torn Syria. Ultimately, it fears emergence of an independent Kurdish state embracing parts of Iraq, Syria and Turkey.
Violence has also spread beyond the Kurdish southeast.
In Istanbul, the PKK's youth wing claimed responsibility for the murder of a shopkeeper who the militants said belonged to Islamic State, the Hurriyet newspaper said.
The Turkish military reported a series of attacks by the PKK on Wednesday, though no casualties were reported.
In the eastern province of Tunceli rebels opened fire on a military base, triggering a brief clash. In Van, near the Iranian border, militants set fire to trucks and opened fire on troops, the military said in a statement.