Reports say hundreds of Syrians have been gathering on the northern border with Turkey, preparing to cross over if the Syrian army advances further into the area after seizing the rebellious town of Jisr al-Shughour.
Syrian security forces announced on Sunday they had retaken Jisr al-Shughur after army troops, backed by helicopter gunships and tanks, moved into the northern town.
Almost 7,000 Syrians have so far crossed the border with Turkey to escape violence, and an estimated 10,000 more are waiting for the opportunity to cross.
The refugees are making use of unofficial border crossings.
Witnesses said those still in Syria had taken shelter among trees near the border since forces moved into the northwestern province of Idlib.
The uprising, now in its third month, seeks an end to Bashar al-Assad's one-party rule, more political freedom and an end to corruption and poverty.
Some residents of northern Syria who have fled the army assault spoke out on Monday, saying troops had begun fighting among themselves in the midst of the military operation.
"The troops are divided. Four tanks defected and they began to fire on one another," the AFP news agency quoted 35-year-old Abdullah as saying.
He fled Jisr al-Shughur on Sunday and crossed the border into Turkey in order to find food.
"When they started to fire on each other, I decided to flee," he told AFP.
Al Jazeera speaks to a resident in Jisr al-Shughur
about the situation there on Sunday
Abdullah, who like many other refugees would only give his first name, said that troops had pounded Jisr al-Shughur with heavy gunfire at the start of the assault.
Al Jazeera's Anita McNaught, in Guvecci on the Turkey-Syria border, spoke to Syrian refugees inside the camp in Turkey.
One of them said he saw two military helicopters hovering over Jisr al-Shughur and heard reports of indiscriminate shooting.
Another Syrian gave this account after Al Jazeera smuggled a camera into the refugee camp: "We were besieged in Jisr yesterday. We couldn't leave. They shot at everyone, I was shot in the chest, My cousin, who was with me, died.
"They cut our electricity and water. We were left with nothing, that is why we came to the Turkey border."
Syrian state television said army units fought "armed groups" on Sunday, but residents and activists said troops had clashed with mutinous soldiers defending the town alongside residents.
"Army divisions entered Jisr al-Shughur and purged the state hospital of armed groups," the television said.
"Two members of the armed organisations were killed, large numbers of them arrested, and lethal weapons in their possession were seized."
On the diplomatic front, a spokesman for David Cameron, the British prime minister, said on Monday that Recep Tayyip Erdogan, the Turkish leader, had expressed support on Monday for Britain's efforts to put pressure on Syria at the UN Security Council.
"Prime Minister Erdogan welcomed the UK's efforts to put pressure on the regime through a Security Council resolution and they agreed that Britain and Turkey should work hand in hand to achieve this," the spokesman said.
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He said the two leaders noted that "the situation had deteriorated markedly in the last week and agreeing that the violence was a cause of deep concern.
"They agreed on the importance of international unity in response to a crisis that is increasingly dangerous for the Syrian people and the region."
The crackdown and the resultant misery have heaped on civilians trapped in the ongoing violence have been globally condemned.
The White House accused the Syrian government on Saturday of creating a humanitarian crisis and urged it to halt its crackdown on civilians and give the Red Cross immediate, unfettered access to the country's northern region.
"Syrian leaders have no excuse for denying humanitarian assistance by a neutral body like the ICRC," the White House said. "If Syria's leaders fail to provide this access, they will once again be showing contempt for the dignity of the Syrian people."
Jisr al-Shughur siege
Human-rights groups say Syrian security forces have killed more than 1,300 civilians in bloody efforts to suppress the anti-government demonstrations.
Some residents of Jisr al-Shughur who fled to Turkey have told the Associated Press that thousands of young men, including soldiers and police who switched sides and joined the uprising against Assad, had armed themselves and planted dynamite at the town entrances.
Troops and tanks had laid siege to Jisr al-Shughur after authorities said the would retaliate against the reported killings of 120 security personnel last week.
Syria's state television reported on June 6 that security personnel had been killed in an ambush, but refugees and rights groups said the dead were mutinous soldiers, shot for refusing to fire on civilian protesters.
Reports said troops removed 10 uniformed bodies from a mass grave in front of the military police building on Sunday.
At least four of the bodies were beheaded or struck on the head with an axe, according to an AP reporter who was invited to accompany the Syrian forces.
Source: Al Jazeera and agencies