GENEVA - Syrian troops stormed villages close to the border with Turkey on Thursday, hunting armed military defectors who fought back in clashes that left at least four soldiers and three others dead, activists said.

The fighting in the country's restive northern region of Jabal al-Zawiya, where Syrian military defectors are active, was the latest sign of a trend toward growing militarization of the 7-month-old uprising.

The Syrian opposition had until recently focused on nonviolent resistance. But since late July, a group calling itself the Free Syrian Army has claimed attacks across the country and emerged as the first significant armed challenge to President Bashar Assad's authoritarian regime.

The opposition has mostly welcomed the armed group's formation, and the movement could propel the Syrian revolt by encouraging senior officers to desert the regime.

But the escalation could also backfire horribly, giving the regime a new pretext to crack down even harder than it already has. The sectarian divide in Syria, where a regime composed mostly of the Alawite offshoot of Shiite Islam rules over Sunnis and others, also means that any insurgency could escalate quickly into civil war.

The UN's human rights office on Thursday raised its tally of people killed during seven months of unrest in Syria to more than 2,900, including members of the security forces. The figure rose by at least 200 since the beginning of September.

Four troops and three others died in Thursday's clashes in villages in the west of Jabal al-Zawiya region, the London-based Syrian Human Rights Organization said. The group did not specify whether the three non-military dead were armed defectors or civilians caught in the fighting.

The Local Coordination Committees activist group had no confirmation of the soldiers' casualties but said three people died in military operations which were accompanied by intense shooting from heavy machine guns.

Syrian defectors armed mostly with rocket propelled grenades and guns operate mainly around Jabal al-Zawiya and also in the central Syrian region of Homs.

Small-scale military defections have been reported in Syria since early on in the uprising and have increased in the past few weeks.

Riad al-Asaad, an air force colonel who heads the Free Syrian Army, said in an interview with The Associated Press Wednesday that the group now has more than 10,000 members.

While analysts said those numbers might be inflated, al-Asaad was confident more soldiers would soon join his ranks. He spoke by telephone from neighboring Turkey where he now seeks safe refuge.

"They will soon discover that armed rebellion is the only way to break the Syrian regime," he said in the interview. "I call on all the honorable people in the Syrian army to join us so we can liberate our country," he added.

"It is the only way to get rid of this murderous regime."