Russian Foreign Minister Sergei Lavrov on Wednesday accused Western powers of encouraging terrorism in Syria, due to their refusal to condemn the suicide bombing in Damascus last week that killed top Syrian defense officials.

"In other words, they are saying, 'We will continue to support such terrorist acts until the UN Security Council does what we want it to,'" Lavrov told reporters in Moscow, according to the RIA Novosti News Agency. "This is a chilling position."

Lavrov's remarks came as fighting raged on in Syria's second largest city and the country's economic hub Aleppo, days after Syrian government forces cleansed the capital of "armed terrorists," the government's term for the rebels.

A "large number" of troops have been moved from the northwestern province of Idlib to join the fighting in Aleppo, a rebel spokesman told AFP.

"The rebels claimed they were in the 'final stages of liberating' Syria. But don't trust them. It was a psychological warfare," the Syrian ambassador to China, Imad Moustapha, told the Global Times. "In fact, the Syrian army has had unprecedented success in fighting with those armed rebels."

According to Moustapha, Syrian government forces have killed "thousands of" rebel fighters in the latest flare-up of military clashes.

He said that the Syrian government "welcomes" them to fight on the battlefield, rather than use the hit-and-run tactics that the militarily weak rebels resorted to earlier in the 16-month-old uprisings. But the Syrian government still maintains that a political solution to the current crisis could be negotiated any time the rebels are willing to put down their weapons, Moustapha added.

Normality in the capital was gradually beginning to return on Wednesday. Previously emptied supermarkets were replenished with food and vegetables, and traffic could be seen on the streets, despite sporadic gunfire.

Syria's ambassadors to the United Arab Emirates and Cyprus, who are husband and wife, have defected to Qatar, spokesmen for the opposition Syrian National Council said on Wednesday.

They were the second and third senior diplomats to desert President Bashar al-Assad's government after the Syrian ambassador to Iraq Nawaf al-Fares said he joined the opposition two weeks ago.

UN peacekeeping chief Herve Ladsous, who flew to Damascus on Tuesday, said half the military observers of the 300-member UN Supervision Mission in Syria "have for the time being, been sent back to their countries," adding that the UN mission is continuing in a "reduced format."

Turkey on Wednesday closed its border gates with Syria to commercial traffic due to worsening security conditions but will keep them open for refugees, Reuters reported.

Agencies contributed to this story