BEIRUT/MOSCOW- Russia offered "full support" for peace envoy Kofi Annan's efforts to end fighting in Syria on Sunday but said his mission would need more time as forces loyal to President Bashar Assad attacked Homs and other rebel strongholds.Moscow also reiterated its stance that foreign support for the Syrian opposition was the main obstacle to peace, while US President Barack Obama and Turkish Prime Minister Tayyip Erdogan discussed how to get non-lethal aid to the opposition.Western and Arab states have urged Assad to step aside to end violence which the UN says has cost 8,000 lives. Russia, a close ally of Assad, said he is ready to talk to his foes on reform and it is the rebels who must be pressed to negotiate.With the Syrian army on the offensive around the country and the opposition fearing Assad would use any talks to strengthen his forces' position and crack down harder, the prospect of a negotiated peace seemed more remote than ever.Russian President Dmitry Medvedev, who will join Obama for a nuclear security summit in South Korea on Monday, told UN-Arab League Syria envoy Kofi Annan in Moscow he appreciated his efforts to end the violence."This may be the last chance for Syria to avoid a long-lasting and bloody civil war. Therefore we will offer you our full support at any level and in various ways in those areas, of course, in which Russia is capable of providing support."Human shields and heavy shelling New York-based Human Rights Watch published videos, obtained from opposition activists, in which people in civilian clothes walk in front of several armed soldiers and infantry fighting vehicles. Activists say the army had compelled the men to walk in front to protect the soldiers.The statement said that residents reported government forces placing children on tanks and inside security buses."The Syrian army's use of human shields is yet another reason why the UN Security Council should refer Syria to the International Criminal Court," said Ole Solvang, a HRW emergencies researcher.It was impossible to verify reports independently because Syrian authorities have prevented foreign journalists and human rights workers from entering affected areas. Waleed al-Faris, an opposition activist from Homs, told Reuters that Sunday's shelling, using tank and mortar fire, was the worst he had seen."There are ten dead and hundreds wounded," he said. "I have not experienced shelling this heavy since Baba Amr."In the southern province of Deraa, birthplace of the revolt, government forces and rebels clashed on Sunday."Thousands of soldiers and over a hundred military vehicles are attempting to enter the area of Lahat in Deraa province today, but they are clashing with rebels," said Rami Abdelrahman, head of the Syrian Observatory for Human Rights, adding that at least five soldiers and three rebels had been killed.The Syrian state news agency SANA said six "terrorists" had been killed on during dawn raid on a hideout in Deraa.The SOHR said 27 were killed around Syria on Sunday, 15 of them civilians, during heavy shelling in the central city of Homs and northwestern province of Idlib.In the eastern city of Deir al-Zor, Syrian troops conducted house-to-house raids in search of dissidents, SOHR said.