BEIRUT - Syrian troops clashed Thursday with armed men believed to be military defectors in a southern village and a northwestern town, killing at least 13 people in the latest sign that the 7-month-old uprising against President Bashar Assad is becoming increasingly militarized, activists said.

In an attempt by the regime to show it still had the upper hand, the government took journalists on a tour of a central town where the most serious insurrection in recent weeks drew a crushing response. Many buildings in Rastan were burned, shops were shuttered and soldiers manned military checkpoints.

Several residents told of gunmen who they said terrorized the area. And government escorts displayed rifles and other light weapons they insisted had been seized from gangs or terrorists, rather than army defectors.

Despite the spiraling violence and continuing protests, Assad said Syria has "passed the most difficult period" and is now working to become "a model to be followed in the region." He was apparently referring to promised political reforms, most of which have yet to be delivered. The comments, to a visiting Lebanese delegation, were reported by the official news agency.

Assad, initially regarded as a potential reformer in the Arab world when he came to power upon the death of his father in 2000, responded with a harsh military crackdown when the wave of Arab uprisings reached the tightly controlled country in mid-March. The UN says nearly 3,000 people have been killed.

After months of mostly peaceful protests, the growing involvement of military defectors in confrontations has raised fears that Syria may be sliding toward a civil war. There have also been reports of protesters taking up arms to defend themselves against military attacks.

In the latest clashes, troops stormed the northwestern town of Binnish with more than 50 vehicles on Thursday. The sound of explosions and gunfire could be heard. The London-based Syrian Observatory for Human Rights and another activist group, the Local Coordination Committees, said five people were killed.

Rami Abdul-Rahman, who heads the observatory, said six soldiers and two defectors were also killed Thursday in the southern village of Harra in Daraa province, where the uprising began. He said an army force appears to have been ambushed in Harra's main square.

Syrian authorities have prevented journalists from independently visiting places of confrontation in the uprising and have banned all but a few foreign journalists from entering the country.

On Thursday, the government organized a trip for local reporters to the rebellious central town of Rastan, which is home to about 70,000 people.

Troops backed by tanks retook the town on Oct. 2 after five days of heavy fighting with defectors.

Many shops, homes and government buildings bore the scars of heavy fighting. Some buildings were entirely blackened by fire; others were marked with a spray of bullets.

A clock tower in the centre of Rastan was surrounded by sand bags.

The governor of the province of Homs, where Rastan is located, said nearly half of all government institutions in the town were damaged and telephone and electricity lines were cut by armed groups.

Governor Ghassan Abdul-Aal told reporters the situation is getting better in the area, pledging that reconstruction work will be finished by the end of this month.

He denied the armed men who had controlled Rastan were defectors. He said those gunmen arrested were Syrians. The government has largely blamed "terrorists" and foreign plotters for the country's unrest.

Journalists were also shown weapons that authorities say they seized, including nearly 200 shotguns, assault rifles, pump-action rifles, military uniforms and rocket-propelled grenades.

Mohammed Syouf, a 24-year-old Shop owner, told an Associated Press reporter that "armed groups stormed banks, military centres and ransacked them," adding that residents appealed to the army to enter the city "to rid it of those gunmen."

Mohammed Najjar, 18, said the gunmen were from inside and outside Homs.

"They torched public properties, terrorized people and prevented residents from going to their jobs," he said.

Since the uprising began, Assad made promises of sweeping reforms but most have not been carried out and the opposition says they will accept nothing short of his departure.

On Thursday, senior officials with Assad's ruling Baath party said a committee was set up to amend the constitution to allow for the formation of more political parties and to define presidential terms and elections. Syria has not had presidential elections in decades.