|Video has emerged that claims to show government troops supporting 'thugs' in tackling protesters [Al Jazeera]
Syrian security forces are reportedly widening an operation in the north of the country aimed at cracking down on anti-government protests amid reports of defections from the army's ranks.
Troops pushed towards the town of Maarat al-Numaan after detaining hundreds of people in a sweep through villages near Jisr al-Shughur, the Reuters news agency reported on Tuesday, citing residents who fled the area.
Refugees have poured across the Syrian border into neighbouring Turkey to escape the government's operation in Jisr al-Shughur, the site of a military takeover on Sunday.
More than 8,000 Syrians have so far crossed the border with Turkey to escape the violence, and an estimated 10,000 more are waiting for the opportunity to cross.
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 channel said. "Two members of the armed organisations were killed, large numbers of them arrested, and lethal weapons in their possession were seized."
Discussing the reported divisions within the Syrian army on Tuesday, Anas al-Abdah, chairman of the opposition group, Movement for Justice and Development, told Al Jazeera: "Many in the Syrian army feel uneasy about the systematic policy of targeting civilians and attacking peaceful demonstrators that is being imposed on them by the political and military leadership.
"Many defected from the army in order to protect the civilians. This happened previously in Daraa and Homs, and now, more evidently, it is happening in Jisr al-Shughur.
Al-Abdah said that almost a week ago, military officers began to notice that people from a paramilitary militia called Shabiha, which is alleged to be working with the Syrian security forces, had started wearing military uniform.
|Joshua Landis of the University of Oklahoma's Middle East studies unit discusses the Syrian defection claims
"This caused huge resentment within the army because these paramilitary militias were committing atrocities against civilians," he said.
"We have strong evidence that indicates that the state security branch in Jisr al-Shughur defected from the main branch in Damascus, and they were severe clashes between the state security and the military intelligence in Jisr.
"This in itself is a very worrying development for the Syrian regime."
Al Jazeera's Anita McNaught, in Guvecci on the Turkey-Syria border, spoke to Syrian refugees inside the camp in Turkey on Monday.
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."
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 for Britain's efforts to put pressure on Syria at the UN Security Council.
In-depth coverage of escalating violence across Syria
"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.
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".
The Syrian 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.
The crackdown and the resultant misery heaped on civilians trapped in the ongoing violence have been globally condemned.
Human-rights groups say security forces have killed more than 1,300 civilians in bloody efforts to suppress the anti-government demonstrations.