Turkey says a translator and two Syrians have been injured by shots fired into a refugee camp from the Syrian side of the border.
The incident is the first of its kind since Turkey started sheltering thousands of Syrian refugees fleeing the deadly violence in their homeland.
A Turkish foreign ministry official said the Kilis refugee camp came under fire from the Syrian side of the border overnight.
“After this incident the Syrian Charge d’Affaires in Ankara was called and we demanded an end to this,” the official said.
Mohammad Abdelqader, a refugee in the camp who claimed he had witnessed the shootings, said two Syrians had been killed and two more had been wounded in the attack. This version of events cannot be confirmed.
Elsewhere activists say Syrian military forces killed 30 people on Monday, mostly women and children, when they bombarded a town in the central province of Hama.
They said 17 children and eight women were among those killed in al-Latmana, northwest of the city of Hama. Activists said 40 people were killed in an army attack on the same town two days earlier.
Read more: Inside 'free' Syria
International mediator Kofi Annan will visit a camp for Syrian refugees in Turkey on Tuesday en route for talks with senior officials in Iran, his spokesman Ahmad Fawzi said on Monday.
Annan will visit Syrian refugees staying in a camp in Hatay, he said. Thousands of Syrian refugees are sheltering in eight camps set up in Turkey’s southern provinces of Hatay and Gaziantep, and others have crossed into Lebanon, Jordan and Iraq.
“At the moment we have 24,000 Syrians who have entered Turkey. Of course this number is rising,” Turkish Prime Minister Tayyip Erdogan said on Saturday before departing on a trip to China.
Annan has put forward a six-point peace plan for ending the year-long fighting that lays down a deadline for Syria to withdraw troops and heavy weapons from towns on Tuesday, followed by a ceasefire by both Syrian forces and opposition fighters 48 hours later on 12 April.
Syria on Sunday demanded written guarantees that insurgents would stop fighting before it would pull back its troops under the terms of his plan, and a rebel leader said the initiative was doomed.
Annan, in a statement issued later on Sunday, said an “unacceptable” escalation in violence in Syria violated guarantees made to him and called on Damascus to keep its promises to end the bloodshed.