Syrian troops pressed an offensive near Lebanon on Saturday, heavily bombarding a rebel-held town and forcing many residents to flee to safety across the border, activists said.

The violence came as an activist group said the death toll in the three-year Syrian conflict has reached 140,000. The Britain-based Syrian Observatory for Human Rights said the figure includes civilians, rebels, members of the military, pro-government militiamen and foreign fighters.

The group based its count on information from a network of informants on the ground.

The group said violence had escalated of late, with more than 3,400 people killed so far this month even as the government and opposition hold peace talks in Geneva. Since Jan. 22 when talks began, 5,792 people have been killed.

U.N.-Arab League mediator Lakhdar Brahimi ended a mere half hour of direct talks between the Syrian government and opposition Saturday with the situation still at an impasse and the future of negotiations in in doubt. No date was set for a third session.

The U.N.'s human rights office said in January it had stopped updating its own tally of the Syrian dead because it can no longer verify the sources of information that led to its last count of at least 100,000 in late July.

Also Saturday, the main opposition group in exile, the Syrian National Coalition, said its leader entered rebel-held areas in the northwestern province of Idlib a day earlier. Moderate rebels in the area are fighting government forces on one front and members of the Al Qaeda-breakaway group, the Islamic State of Iraq and the Levant.

"I have come here to say we are with you.  We are connected with this land and will not compromise on the values of this Revolution. We will get rid of this corrupt and criminal family who has been ruling this country for decades," a coalition statement quoted Ahmad al-Jarba as saying, referring to the Assad dynasty that has ruled Syria since 1970.

It was not the first visit by al-Jarba to rebel-held areas, but is significant because it came as the Geneva peace talks flounder. Al-Jarba spends much of his time in Turkey.

The Observatory said the government shelling concentrated on the town of Yabroud as well as nearby villages of Sihil and Falita. It had no immediate word on casualties.

State-run Syrian TV said troops killed several members of Al Qaeda-linked Jabhat al-Nusra in the hamlet of Rima Farms on the edge of Yabroud. It added that large amounts of ammunition were also destroyed by government forces in the area.

Amer al-Qalamouni, an activist in the area, told The Associated Press via Skype that poor weather had grounded government warplanes. "Most of today's shelling is either artillery, mortar or with tanks," al-Qalamouni said.

He said government troops were backed by members of Lebanon's militant Hezbollah group, which openly joined President Bashar Assad's forces in the battle against opposition forces last year. He said the fighting was concentrated in areas near Yabroud such as Rima Farms and Qastal.

The army along with Hezbollah fighters has been on a crushing offensive in the Qalamoun region since early December, trying to sever a main thoroughfare for rebels from Lebanon. Yabroud, which has a large Christian population, is the last major town in the region to still be held by rebels.

Kasem Alzein, a Syrian doctor who lives in the Lebanese border town of Arsal, said six wounded people were brought from Syria for treatment early Saturday. A long line of cars and trucks carrying people are fleeing toward Lebanon, he added.

Alzein said about 1,000 families and some 35 wounded people have arrived in Arsal over the past days. The town's population has almost doubled over the past two years because of the flow of Syrian refugees.

In the capital Damascus, Syrian state TV quoted Palestinian official Anwar Raja as saying that officials entered the contested refugee camp of Yarmouk Saturday to make sure that fighters who are not from the camp have left.

Syrian authorities have allowed the flow of thousands of food parcels into the camp over the past weeks on the condition that gunmen who are not Palestinians from the camp leave.

A government siege of Yarmouk that is home to some 18,000 people has been in place for about a year, and activists estimate more than 100 people there have died of hunger-related illnesses and a lack of medical aid.