Opposition demands tougher action on Assad Syrian opposition activists piled on pressure for tougher international action against President Bashar al-Assad's regime, after UN peace observers suspended their mission and world powers prepared for crucial talks this week. The Syrian National Council, an umbrella anti-regime group, said the world must "assume its responsibilities" to protect Syrians, amid reports of eleven more deaths in the battered central city of Homs as the army intensified shelling after the monitors" decision. "They can't just pull out and leave Syrians being killed," said Mousab al Hamadee, an activist in the central province of Hama. Either they declare clearly that their mission has failed, urging the international community to have more effective measures ... or [they] keep documenting the crimes of the regime until there is another UN move. The UN team's weekend decision to suspend their eight-week old mission, citing concerns about the observers" own security, throws the spotlight on to efforts to use this week's G8 summit of world powers to end the deadlock between the US and Russia over action on Syria. Presidents Barack Obama and Vladimir Putin are due to discuss Syria's 15 month crisis at a bilateral meeting on Monday, while the head of the UN mission in the country is due to report to the UN Security Council on Tuesday about the situation more than two-months after the start of a much-breached ceasefire. The Local Coordination Committees, an on-the-ground activist network in Syria, attacked the suspension of the monitoring mission, as an "arbitrary decision" made even though there were "no alternative plans." " (It) comes with an expansion of the regime's military operations ... it is unjustifiable and unacceptable that the international community would abandon its responsibilities," the group said. The SNC called for a UN Security Council resolution that would offer the option of using military force against the regime to stop a conflict already estimated to have left well over 10,000 people dead. The SNC - which has struggled to establish itself as the authoritative voice of the fragmented uprising - said a grouping of anti-Assad international powers known as the Friends of Syria should take unilateral action if Russia and China vetoed security council action for a third time. "We can still put an end to the horrors," said Abdel Basset Sayda, the new SNC leader, at a press conference in Istanbul. There must be a resolution at the international level. Major General Robert Mood, head of the near 300-strong unarmed observer mission in Syria, said observers would stop patrolling until further notice because of rising violence, which has included attacks on monitors" vehicles. An Arab League peace observers" mission in Syria earlier this year collapsed shortly after a similar suspension. The UN observers are in the country to supervise implementation of a six point international peace plan breached repeatedly by both Assad loyalists and the armed opposition groups that sprung up against him after his security forces cracked down brutally in the uprising's early days. While Kofi Annan, the international envoy who wrote the plan, has criticised both sides, he has also stressed that the much better armed government forces bear the primary responsibility for ending the violence. Mr Assad - whose family have ruled Syria for four decades - says the revolt against him is a foreign-backed terrorist plot that must be crushed. He has said he is prepared to have talks with opponents not involved in violence.