BEIRUT (AP) -- Troops loyal to Syrian President Bashar Assad shelled two restive central cities and sent tanks and snipers into battle against rebels in the capital's suburbs on Friday, broadening an offensive that appeared aimed at crushing pockets of opposition less than a week before an internationally sponsored cease-fire is to take hold, activists said.
With fighting escalating, the stream of Syrians fleeing to neighboring Turkey picked up considerably this week. Turkey's disaster management agency said more than 2,700 refugees arrived on Thursday and early Friday, pushing the total to nearly 24,000.
Thick black smoke billowed from a residential area in Syria's central city of Homs as the sounds of heavy gunfire and explosions could be heard. "Intense shelling by Assad's gangs," a man could be heard saying while filming what appeared to be a house on fire. "May God help us."
Regime forces also struck the town of Rastan, just north of Homs, with heavy machine-guns and mortars, said the Britain-based Syrian Observatory for Human Rights. Ground troops later tried to push their way into the city, clashing with opposition fighters, the group said.
The government has been laying siege to Rastan since rebels took control of it in late January. Rebels are in control of Rastan town -- but not the strategic Rastan bridge, which is the main link to the country's north. Over the past year, the rebels have tried repeatedly to overrun the bridge and break the siege.
Government forces also broadened an offensive in the Damascus suburbs of Douma, Saqba and Arbeen, exchanging fire with rebels, activists said. The Observatory said three members of the military were killed.
Tanks patrolled deserted streets in the sprawling Douma district, about 8 miles (12 kilometers) outside Damascus, said activist Mohammed Saeed. Snipers set up positions atop a 12-story medical building.
Troops had entered Douma on Thursday in what activists described as one of the most violent raids near the capital since the uprising against Assad began more than a year ago.
Plumes of smoke rose above Saqba, and activists said regime forces torched at least one house.
U.N. Secretary-General Ban Ki-moon warned Thursday that the Syria crisis is getting worse, even as a cease-fire is to take hold by 6 a.m. on Thursday. The truce deal was brokered by Kofi Annan, the special U.N. and Arab League envoy to Syria.
"Cities, towns and villages have been turned into war zones. The sources of violence are proliferating," Ban told the U.N. General Assembly. "The human rights of the Syrian people continue to be violated. ... Humanitarian needs are growing dramatically."
The escalating fighting has dimmed hopes that a year of fighting, which the U.N. says has claimed more than 9,000 lives, will end soon.
Assad last week accepted the truce deal, which calls for his forces to pull out of towns and cities by Tuesday. However, Western leaders have cast doubt on his intentions, suggesting he is playing for time and is not serious about the Annan plan which is to pave the way for talks between the regime and the opposition on a political solution.
Opposition activists say they believe Assad's regime is stepping up attacks to gain ground ahead of a truce.
Thousands of refugees were streaming into neighboring Turkey to escape the assault.
Hikmet Saban said he fled after Syrian forces raided the village of Taftanaz, close to the city of Idlib in northwestern Syria earlier this week. Saban said he saw dozens of bodies in Taftanaz.
"Most of the bodies were burnt and were impossible to recognize," he told Turkey's state-run Anadolu Agency. "They devastated Taftanaz, all houses demolished, everything destroyed. Helicopters and tanks are bombarding continuously. Taftanaz has been burnt to the ground for three days. "
On Friday, a small UN advance team headed by a Norwegian major general, Robert Mood, was to meet with Syria's deputy foreign minister to discuss the cease-fire plans. Mood is to set up a UN monitoring force with 200 to 250 members if the peace plan succeeds.
Meanwhile, the International Committee of the Red Cross has been able to dispatch a convoy with aid supplies for 2,000 displaced families to Tartous, one of the areas of fighting in Syria, said Annan's spokesman, Ahmad Fawzi.
AP Writers Bassem Mroue in Beirut and John Heilprin in Geneva contributed to this report.