Syrian forces bombard rebels near Latakia A photograph said to show Free Syrian Army rebels in Idlib province. Syrian forces have unleashed a new round of heavy shelling and sent reinforcements to a mountainous area near the coastal city of Latakia where hundreds of rebels have set up base and which has been the scene of fierce fighting in recent days, activists say. The fighting between government troops backed by helicopter gunships and armed groups in the area of Haffa began on Tuesday. An opposition group said at least 58 soldiers had been killed and more than 200 wounded in the operation there since. Rami Abdul-Rahman, director of the Britain-based Syrian Observatory for Human Rights, said the heavy losses indicated the seriousness of the challenge in the mountainous area where "hundreds" of rebels were entrenched. His estimated death toll could not be independently verified. The state-run news agency Sana said "terrorist groups" in Haffa had attacked public and private institutions on Saturday and committed "heinous" crimes against civilians, setting fire to the national hospital and forcing people to leave their homes. It said troops had killed a number of them and arrested several others, adding that it was still pursuing gunmen and working to restore security to the area. Six children were among 10 people killed by a shell that exploded in a house where they had taken cover during the fighting in the region on Saturday, the Observatory said. In Homs province at least 35 people have been killed in Syrian army bombardment over the past 24 hours, opposition activists said on Sunday. The bombardment targeted opposition strongholds in the city of Homs and the nearby towns of Qusair, Talbiseh and Rastan, where Free Syrian Army rebels have been escalating attacks on army patrols, roadblocks and missile batteries, the Syrian Network for Human Rights and other opposition campaigners said. The British foreign secretary, William Hague, said the situation in Syria resembled Bosnia in the 1990s, as he warned time was running out to stop the killings in the country. Hague said it was now up to Russia to use its leverage with President Bashar Assad's regime to bring an end to the brutal violence in Syria. He told Dermot Murnaghan on Sky News the continued political and trade isolation of Syria was the second best option. What was needed was a united way forward, he said. Asked whether the government had ruled out military intervention, Hague said: "I think we don't know how things are going to develop. Syria is, as I said in the last couple of weeks, on the edge of a collapse or of a sectarian civil war so I don't think we can rule anything out. But it is not so much like Libya last year, where of course we had a successful intervention to save lives. It is looking more like Bosnia in the 1990s, being on the edge of a sectarian conflict in which neighbouring villages are attacking and killing each other, so I don't think we can rule anything out. But it does mean ... there is an increasing commonality of analysis with Russia. The Russians are concerned about that scenario. He said the UK and Russia agreed that Assad did not have to be in charge in Syria but a way forward could not be found while the violence continued. Russia now had to use its "leverage" to ensure the Syrian regime ended the violence, he added. Hague said he "welcomed in principle" the Russian proposal for an international conference on Syria, but warned it must "lead to a change and not just buy time for the regime to kill more people." He said the way forward was to adopt the peace plan drawn up by the international envoy Kofi Annan. But he said it would be hard to see how Iran could attend the conference, which is one of Russia's demands, as it had already given Syria technical support and advised the regime how to suppress protests. The British government has already provided £8.5m towards helping alleviate the "appalling" humanitarian situation, he said. Thousands have been killed since the Syrian uprising began in March last year. The UN's latest estimate is 9,000 dead, but that is from April and the world body has been unable to update the figure since. Syrian activists put the toll at more than 13,000. Annan brokered a ceasefire that went into effect on 12 April but has since been violated every day by both sides of the conflict. Armed rebels have stepped up their attacks on government troops recently, taking their fight against Assad to the capital, Damascus, which on Friday saw some of the most intense fighting since the 15-month uprising began. In northern Syria, thousands of people took part in the funeral for nine people who died in reported shelling on Saturday night in the town of Maaret al-Numan in Idlib province. Amateur video posted online by activists on Sunday showed a large crowd taking part in the funeral procession. The victims were placed on makeshift stretchers which were carried in the streets as people chanted and mourned.