Arab and Western powers will challenge the Syrian regime to accept a proposal to allow in humanitarian aid at a so-called \"Friends of Syria\" meeting in Tunis on Friday, a US official said. US Secretary of State Hillary Clinton discussed the \"unified humanitarian proposal\" with counterparts on the sidelines of an international conference on Somalia in London on Thursday, the official said on condition of anonymity. \"The challenge is on the Syrian regime to respond to this,\" the official said. \"I think one of the things you are going to see coming out of the meeting tomorrow are concrete proposals\" on the supply of aid \"within days\", added the official. The proposal comes two days after the International Committee of the Red Cross called for a daily truce of two hours in Syria so it can deliver vital aid to afflicted areas. More than 7,600 people have been killed in the 11 months since the uprising in Syria began, according to the British-based Syrian Observatory for Human Rights. The Friends of Syria meeting on Friday is the group\'s first since it was created in response to a joint veto by China and Russia of a UN Security Council resolution condemning a bloody crackdown on protests in Syria. British Foreign Secretary William Hague said earlier that he would push for a tightening of the diplomatic and economic \"stranglehold\" on Syria at the Tunis meeting. \"I will be discussing today with Hillary Clinton and many of the Arab leaders what we can achieve at that meeting. I think part of that has to be tightening a diplomatic and economic stranglehold on the Assad regime,\" he told the BBC. The British Foreign Office would not comment on the outcome of Thursday\'s talks on the Tunis meeting.