Syrian forces fired on a refugee camp inside Turkish borders on Monday, killing at least one person and wounding several others, activists say.

The Britain-based Syrian Observatory for Human Rights said the incident began with a clash between opposition fighters and Syrian forces at the Salameh border crossing.

A spokesman for the Observatory, Rami Abdul Rahman, said the fighting spilled over into Turkey, with eight opposition fighters escaping to the refugee camp under fire from Syrian forces.

He said five people were injured in the camp and one later died of his wounds. Several Syrian soldiers were also killed in the fighting, he said.

The Turkish foreign ministry has not confirmed the death. The local governor, Yusuf Odabas, said the wounded included three Syrians, one Turkish translator and one Turkish policeman.

There has so far been no response from Syria about the alleged attack.

The incident reportedly occurred near the southeastern town of Kilis, where Turkey has set up a camp for Syrian refugees. Around 25,000 Syrian refugees are currently housed in three Turkish provinces on the border to Syria, having fled the regime's bloody repression of year-long anti-government protests.

The international mediator for Syria, Kofi Annan, is to visit some of the refugee camps on Tuesday, according to a Turkish diplomatic source.

The official told the AFP news agency that the former UN chief would visit the camps for a few hours ahead of a trip to Iran.

Peace plan endangered

This comes as a peace plan put forward by Annan and agreed to by Syrian President Bashar al-Assad seems in jeopardy.

On Sunday, the Syrian government said it would only keep its pledge to withdraw troops from protest hubs if rebels gave written guarantees that they would stop fighting. Riad al-Asaad, commander of the rebel Free Syrian Army, said his group was ready to abide by the truce but that it does not recognize Assad's government and therefore "will not give guarantees."

The foreign ministry of China, which has backed Assad in the UN Security Council, urged the Syrian government and opposition groups on Monday to "grasp this important chance" and "abide by their commitments to cease fire and withdraw troops."

Under Annan's peace deal, the Syrian army was to pull out of protest cities on Tuesday, and a complete end to fighting was scheduled for early Thursday morning.

But escalating violence over the weekend claimed almost 180 lives, most of them civilians. Activists say there is not sign of any troop withdrawal from any area of fighting.

In the latest fighting, the Britain-based Syrian Observatory for Human Rights said 12 soldiers were killed in fierce clashes between the army and rebels in the northern Aleppo region and Deir Ezzor in the east. It also reported army operations in other parts of the country.

Summary executions

Human Rights Watch has meanwhile claimed that Syrian security forces and pro-regime militias have executed more than 100 civilians and rebel fighters in attacks on protest hubs since late 2011.

It says most of the executions were carried out last month. At least 85 of those killed were civilians who were not involved in fighting, including women and children, according to the New York-based watchdog.

The UN estimates that more than 9,000 people have been killed since the conflict started in mid-March 2011.

tj/acb (AFP, dpa)