MOSCOW - Russia Monday said the Syrian authorities were prepared to hold talks in Moscow to end escalating violence but the opposition refused to come to the table unless President Bashar al-Assad stepped down.Russia, which has resisted Western calls to back UN sanctions against Damascus, had suggested to both Assad's regime and the opposition that they should meet in Moscow for "informal contacts" without any preconditions. "Our offer has already received a positive response from the Syrian authorities," the foreign ministry said.But the head of the opposition Syrian National Council said that the opposition rejected all such talks with the Damascus regime until Assad steps down."The resignation of Assad is the condition for any negotiation on the transition to a democratic government in Syria," Burhan Ghalioun told AFP.The Russian foreign ministry had warned the Syrian opposition that Moscow was counting on its participation in the talks."We are expecting that the opposition will also give their assent in the next days and put the interests of the Syrian people before any other ideas," it said.Moscow's diplomatic moves come at a time of mounting concern that the clashes between the opposition and regime forces have become even deadlier with 80 people killed across Syria on Sunday alone, according to activists. This is on top of what the United Nations said at the start of January already amounted to 5,400 deaths in the standoff.Russia also appears keen to prove it is playing a constructive role to defuse the crisis, amid mounting Western frustration over Moscow's refusal to support a UN Security Council resolution condemning the Assad regime.The foreign ministry said that the talks in Moscow were "acutely necessary for the immediate cessation of all violence in Syria and preventing a bloody split in society." They would also help ensure the "success for profound democratic changes in the country, in line with the hopes of all Syrians." Russia said its offer to host talks was motivated by its desire to see an end to the crisis "through a peaceful mechanism worked out by the Syrians themselves, without international interference."  Moscow still maintains close ties with the secular regime in Damascus that were cultivated under Assad's father and strongman predecessor Hafez al-Assad and extend to having a naval base in the country and supplying arms.European and Arab nations on Friday pressed for UN Security Council backing for an Arab League plan calling on Assad to stand down, but Russia said their proposed resolution crossed its "red lines."Russia has repeatedly condemned the West for what it says is a one-sided approach on Syria and said that both the opposition and the Assad regime are equally to blame for the violence.At least 21 civilians, six members of the security forces, and two deserters were killed in violence across Syria on Monday, the Syrian Observatory for Human Rights said.Near the capital, meanwhile, troops penetrated Rankus, 40 kilometres (25 miles) north of Damascus, after shelling the town which had been encircled for the past six days, the Observatory said. It said at least 17 civilians were killed in Homs in central Syria. Security forces stormed the flashpoint city, killing a family of six and a young girl, who was hit by gunfire from a checkpoint in the Karm al-Zeitun district, according to the Britain-based rights group.Another civilian was killed by gunfire in Karm al-Zeitun, and one in the neighbourhood of Al-Khalidiyeh, also in Homs.Four civilians were reportedly killed in the Qussur district, while another was hit by machinegun fire in Baba Amro and a man was shot dead by sniper fire in the city's Wadi Iran quarter.A young man was shot dead in town of Qusseir in the Homs province, the Observatory said.It claimed that unidentified assailants killed a doctor in Shammas, also in Homs, while the state news agency said Dr Mustapha Safar was shot dead by a "terrorist group." Separately, rebel soldiers "attacked a minibus carrying six security officers on their way to make arrests in Hirak, killing all of the passengers," said the Observatory, in statements received in Nicosia.Government forces responded by deploying two tanks which opened fire and killed three civilians in the southern city of Daraa, it said. Elsewhere in the province of Daraa, cradle of the 10-month uprising against President Bashar al-Assad's regime, a civilian was killed by indiscriminate gunfire in the town of Saida, the watchdog added.Near the capital, the Observatory and activists at the scene said deserters pulled out of Rankus as the army moved in. The military assault reportedly claimed the lives of two deserters and left dozens of civilians wounded.In the eastern suburbs of Irbin and Hammuriyeh, snipers were "shooting at everything that moves," the watchdog said.Armed clashes also erupted between the army and mutinous soldiers in Hirak, further south in Khirbet Ghazaleh and Saida, as well as in Nassib, a village on the border with Jordan.Meanwhile, the Syrian state news agency reported a "terrorist group" attacked a gas pipeline in Homs province, near the border with Lebanon."An armed terrorist group has targeted a pipeline between Homs and Banias, near the town of Tal Kalakh, in a sabotage operation," SANA reported, without elaborating.Syrian cities have been subjected to energy shortages for several weeks, which the authorities blame on "armed terrorist groups."The opposition says the regime carries them out to punish protest hubs.Since mid-March, Assad's regime has faced an unprecedented protest movement. The United Nations estimated at the start of January that more than 5,400 people had been killed in the ensuing crackdown on dissent.