Russia has urged the warring sides in Syria to halt their almost two-year conflict and start talks, warning that both sides risk "mutual destruction."

Sergei Lavrov, Russia's foreign minister, said on Wednesday that Moscow was working to encourage dialogue between the rebels and the regime of President Bashar al-Assad.

"Neither side can allow itself to bet on a military settlement as this is a path to nowhere, a path to mutual destruction," he said, following a meeting Arab League chief Nabil el-Araby and other top Arab diplomats.

Lavrov, who on Monday is due to host Syrian Foreign Minister Walid al-Muallem for crucial talks, said: "There are signs of positive tendencies, signs of tendencies for dialogue both from the side of the government and the opposition."

But he said it was up to the two sides to decide what kind of dialogue might take place and at what level.

"It is important that they do not come out with any conditions for each other, and say that I am going to talk to this person but not that one," Lavrov said.

Russia is also expecting a visit in March from opposition Syrian National Coalition leader Mouaz al-Khatib, who has previously been unwilling to visit Moscow due to its support for the regime.

"We are agreeing a date of a visit here by Mr Khatib, which will probably happen at the start of March," Lavrov said. He said the diplomacy was aimed at "creating the conditions for the start of direct dialogue" between the regime and opposition.

Moscow still keeps close ties with Assad, and has so far refused to halt military cooperation with Damascus.

Fighting escalating

The fighting in Syria, which according to the UN has claimed 70,000 lives since the conflict began in March 2011, has escalated over the past few days as both sides press for a military advantage.

Government fighter jets on Wednesday launched air strikes on the Damascus suburb of Daraya and intensified artillery bombardment in several towns around the capital, just a day after rebels claimed they fired mortar rounds at one of Assad's palaces in the heart of Damascus.

Activists said air raids killed at least 14 and caused heavy damage. They also said rebels downed a warplane over the Hammuriyeh suburb of the capital.

In the central city of Homs, rebels gained control of al-Qarabees neighbourhood after heavy clashes with regime forces in the area.

Meanwhile, the Syrian government said the airport in the battleground northern city of Aleppo was still under military control and "safe" from rebels fighting to capture it. Al-Watan, a newspaper considered a mouthpiece for Assad, said on Wednesday the military was "valiantly defending"' the airport and would do so at all cost.

The paper said the airport was under "intensive attacks by gunmen," a rare acknowledgement of the ferocious fighting around Aleppo, Syria's second city.

Assad's troops have been locked in a stalemate with the rebels since July, when Aleppo became a major battlefield in the nearly two-year conflict. The rebels have been trying to capture the airport for weeks.

The UN on Tuesday warned of a growing humanitarian crisis in Syria, as an estimated four million people there are in need of assistance.