The Syrian army has retaken two key rebel strongholds in a major push supported by the Russian air force, a monitoring group said. NATO head Stoltenberg says Russian airstrikes are "undermining" the peace process.
The pro-government troops have retaken Ratyan on the northern outskirts of Aleppo, and Atman in the southern Daraa province, the Syrian Observatory for Human Rights said on Friday.
The move comes as the regime's forces areclosing in on rebel-held Aleppo.
In the previous two days, the government troops and their allies cut off the rebels' main supply route between the city and the Turkish border.
"Taking Ratyan will enable the regime forces to fully control roads around the towns of Nubul and Zahraa, which they recaptured two days ago," the head of the monitoring group, Rami Abdel-Rahman, told the dpa news agency.
According to the Observatory, Damascus' troops were backed by the Iranian Revolutionary Guards and the Lebanese Hezbollah movement, with Moscow providing air support.
The victory in Atman is also a major gain for the regime, as the rebels used the town to launch attacks in the Daraa region, Abdel-Rahman told AFP.
Rebels demanding more weapons
The northerncountryside of the Aleppo province
was now completely encircled, according to a senior officer in the US-backed Free Syrian Army.
"The Russian cover continues night and day. There were more than 250 airstrikes on this area in one day," Hassan Haj Ali told the Reuters news agency on Friday.
The officer also reiterated calls for more military aid from international partners.
"We demand daily more support, but the issue of anti-aircraft (weapons) has become a dream ... the dream that will not come true," he said.
While acknowledging "very heavy battles" in Ratyan, Haj Ali said that regime forces were still not in control of the town.
Bombing the peace talks
Peace talks on Syria were put on hold earlier this week, as the regime's forces launched a fresh offensive with Moscow's aerial backing. Opposition forces have saidthey would not negotiate
until the strikes stopped.
NATO Secretary-General Jens Stoltenberg criticized the Russian campaign on Friday, saying it was raising tensions and damaging the peace process.
"What we have seen is that the intense Russian airstrikes mainly targeting opposition groups in Syria are undermining the efforts to find a political solution to the conflict," he told reporters.
The Kremlin dismissed the criticism as "incorrect."
"Russia is consistently making efforts within the general international framework of seeking a peaceful and political settlement to the situation in Syria," Vladimir Putin's spokesman Dmitry Peskov said.
"At the same time, Russia is providing support to the legitimate leadership of the Syrian Arab Republic in its fight against terror," he added.
The UN Security Council is due to discuss the situation later on Friday, with the Geneva talks on hold until February 25.
dj/ng (dpa, AFP, Reuters, AP, Interfax)