Fierce fighting raged for a third day Tuesday in Damascus as opposition activists warned of a major confrontation in the capital.
The Local Coordination Committees of Syria reported several areas of Damascus witnessed intense fighting, with one area under mortar attack and others rocked by explosions, CNN reported.
"The battle for Damascus is coming," said Abdulhameed Zakaria, a Syrian army colonel who defected and joined the rebel Free Syrian Army.
Besides the third straight day of battles in the capital, the LCC reported warplanes firing on the southern city of Herak, with at least two rockets striking the city.
As fighting continued in Syria, U.N.-Arab league special envoy Kofi Annan was in Moscow Tuesday to meet with Russian President Vladimir Putin.
Russia and China, which have trade ties with Syria, have wielded their vetoes on the U.N. Security Council to block some of the tougher draft resolutions against Syrian President Bashar Assad's regime.
Western countries, including the United States, have been critical of Russia, saying its actions have helped Assad's forces maintain their deadly crackdown on dissidents.
Russian Foreign Minister Sergey Lavrov Monday ripped Western countries trying to change Russia's stance.
"The track record of those who try to make us step aside from this position has a lot of deplorable instances of unilateral military actions, and the results are well remembered by everybody," Lavrov said.
Because of the spreading violence, the International Committee of the Red Cross announced the situation in Syria was a civil war, making international humanitarian law applicable "wherever hostilities take place," the organization said Monday.
The LLC said at least 97 people were killed across Syria Monday, including 30 deaths in Hama alone
On Monday, Morocco became the latest country to expel Syrian diplomats, CNN reported. Syria, in turn, declared Morocco's ambassador persona non grata.
Since the crisis began in March 2011, the United Nations estimates more than 10,000 people have been killed in the violence, but opposition leaders said the death toll is closer to 15,000.
Meanwhile, a top Syrian diplomat who defected said the Assad regime will use chemical weapons if cornered.
Assad will only be ousted by force, "even if he will have to eradicate the entire Syrian people," former Ambassador to Iraq Nawaf Fares told the BBC in Qatar.
This could include using chemical weapons if the regime "is further cornered by the people," said Fares, previously viewed by many in the West as a regime hardliner.
He described Assad as someone with a god complex who believes he and his family "will live forever as rulers of Syria."
He said the Assad family was "clinging to power" and Assad himself had become "a fully fledged criminal like a wounded wolf."
Fares also told the BBC the Assad regime has teamed up with al-Qaida to coordinate major bombings across Syria.
"Al-Qaida is not concerned with the Syrian people or their interests," Fares said. "Al-Qaida is searching for space to move, for support."
U.S. officials have linked al-Qaida to deadly bombings and attacks in Syria for months, mostly through Sunni fighters seeking to topple the Assad regime, not through the regime itself.
U.S. officials have told The New York Times al-Qaida is seeking to exploit the turmoil and reinvigorate its regional ambitions after being sidelined in the initial popular uprisings of the Arab Spring last year.
Assad last week blamed the escalating Syrian violence on a mixture of al-Qaida forces and other foreign terrorists or thugs.
As battles raged, two more officials reportedly defected.
Maj. Gen. Adnan Sillu, the former head of Syria's chemical-weapons program, said in an online video he would now head the opposition Free Syrian Army's joint military leadership.
In addition, Farouk Taha, Syria's ambassador to Belarus until his mission ended six months ago, announced his defection, Syrian National Council sources told Arabic newspaper Asharq al-Awsat.