The Syrian military widened its crackdown on anti-government protesters Tuesday, dispatching tanks to at least two more locations, including a town near the border with Iraq, as the government sought to extinguish an expanding rebellion that has appeared to threaten the army’s cohesion.

Tanks moved into position on the outskirts of the eastern border town of Deir al-Zour, site of some of the biggest protests of the three-month-old uprising against President Bashar al-Assad’s government. Activists said tanks were also converging on the town of Maarat al-Nouman on the highway between Hama and Aleppo, where protesters reportedly burned government buildings over the weekend.

The moves came as Syrians continued to trickle across the border into Turkey, where more than 8,500 refugees are living in tent camps set up by the Turkish authorities. Hundreds more are reported to be waiting on the Syrian side of the border, fleeing the crackdown on the town of Jisr al-Shughour, which government tanks overran Sunday.

Activists said Syrians from other areas in the restive north, including the towns of Latakia and Baniyas, are also heading for the border for the first time since the uprising erupted. Omar al-Muqdad, a Syrian activist in Turkey, said many people have been on the run for months.

“Now they have a safe place to go,” he said, speaking by telephone from Turkey.

The exodus raises the prospect of a prolonged refugee crisis on the Syrian-Turkish border that will heighten tensions between the two countries, which until recently had enjoyed warming relations.

On Tuesday, Turkish Prime Minister Recep Tayyip Erdogan called Assad and urged him to “refrain from violence” and to “draw up a timetable of reforms as soon as possible,” according to the Anatolia news agency.

The call, which was not confirmed by Syrian state news media, indicates that Erdogan has softened his stance since he lashed out at Syria last week for what he called the “atrocities” being committed by its military.

But the deployments Tuesday suggest that the Syrian government has abandoned hope of negotiating reforms with the opposition and instead is intent on annihilating the dissent before it spreads to the armed forces.

“They are neglecting world opinion and are closing in on their inner circle of decision makers to try to crush this before serious defections occur,” said Wissam Tarif of the human rights group Insan.

The crackdown in Jisr al-Shughour came after some members of the security forces apparently staged a mutiny and turned on government loyalists. Although the government’s claim that 120 members of the security forces were killed appears exaggerated, it is clear that some form of violent confrontation occurred in the town, which briefly spun out of government control before the troops moved in and the residents fled.

A video posted on YouTube on Tuesday suggested defections may also have taken place in the desert town of Deir al-Zour, the latest target of the crackdown. It shows members of the security forces celebrating with protesters atop a military truck, although the contents of the video could not be independently confirmed

Earlier defections in other towns have been reported, with none amounting to a serious challenge to Assad’s hold on power. But as the revolt has spread, strains have appeared within the security forces, between the mostly Sunni conscripts, who form the bulk of the army; and the officer corps, which is drawn from the Alawite minority to which Assad belongs.