BEIRUT -- United Nations special envoy Kofi Annan said Monday he was "gravely concerned" about reports of escalating violence in Syria and demanded the entry of U.N. observers into a besieged town in coastal Latakia province.
Annan said in a statement that he was "particularly worried about the recent shelling in Homs as well as reports of the use of mortar, helicopters and tanks" in the Latakia highland town of Haffa.
"There are indications that a large number of civilians are trapped in these towns," said the statement from Annan's office in Geneva.
Opposition activists have reported more than 100 people killed in the last two days, attributing most of the deaths to government shelling, as the military has stepped up its bombardment of Homs and other rebel bastions. Heavy fighting was also reported over the weekend in the capital, Damascus, long a government stronghold.
Activists seeking to oust Syrian President Bashar Assad have reported the increased deployment of helicopter gunships against rebel-held towns and neighborhoods.
The opposition has been reporting territorial gains in recent days, and there have been indications that more sophisticated weaponry and additional funds may be flowing to insurgent forces. Destroyed tanks and armored personnel carriers -- apparently blown up with anti-tank weapons or roadside bombs -- have become a regular feature of opposition video from Syria.
The opposition also says army desertions have stepped up and on Sunday reported the defection of an entire base in the former garrison town of Rastan, north of the battleground city of Homs. Much of Rastan is now in rebel hands, the opposition says.
Claims by both sides of the conflict are difficult to confirm because the government strictly limits the access of outside media.
Homs and nearby towns such as Rastan have long been flash points, but the clashes in Latakia indicate that fighting may be spreading to other areas.
Fierce battles have been reported in recent days in Haffa, a mountain township inland from the port city of Latakia. The government is said to have tight control of the Mediterranean coast, but rebels have seized territory in Haffa and other highland towns, the opposition says, blocking off some road access to and from the coast.
It appears that Latakia province, long regarded as firmly in government hands, has become an important new front in the insurgency.
Each side has accused the other of killing civilians in Haffa. Annan's statement indicates that U.N. observers have not yet been able to enter the town.
Meanwhile, officials announced Monday that Russian Foreign Minister Sergei Lavrov was scheduled to visit Iran on Wednesday to discuss Syria and other issues, including upcoming talks in Moscow on Iran's controversial nuclear program.
In a bid to rescue Annan's faltering six-point peace plan for Syria, Russia has proposed an international conference to include many nations, among them Iran. Washington has balked at the inclusion of Tehran.
-- Patrick J. McDonnell in Beirut and Ramin Mostaghim in Tehran
Photo: An image from amateur video released by Shaam News Network and accessed Monday purports to show smoke rising from shellings by Syrian government forces in the town of Rastan. Credit: Associated Press / Shaam News Network