THE defection of a Syrian general who is a personal friend of President Bashar al-Assad gave a huge boost to anti-government rebels as Western and Arab states met them in Paris on Friday to help prise Assad from power.In some of the strongest U.S. remarks yet on a crisis that has divided the United Nations Security Council along Cold War lines, Secretary of State Hillary Clinton told the Paris conference that Russia and China must "pay a price” for blocking U.N. sanctions that might press Assad into stepping down.As she spoke, Manaf Tlas, a brigade commander in the Republican Guard who attended military college with Assad and fled to Turkey this week, was on his way to Paris, where his father, Assad’s father’s defence minister, has also taken up residence, a close family friend told Reuters.There was no immediate sign that Tlas would throw in his lot with the rebels and an opposition source said he had no plans to attend Friday’s meeting.But his defection is the clearest signal yet that some in Assad’s inner circle think his days in power are numbered, as an uprising that began in March 2011 with a groundswell of peaceful protest turns into a civil war with strong sectarian overtones.While the lightly armed rebels are no match for Syria’s large and well-equipped army, their hope lies in eroding loyalty and conviction within Assad’s establishment to the point where it loses its hold on power.Syrian armour pushed into the rebel-held northern town of Khan Sheikhoun on Thursday, activists said, adding 11 victims to a death toll dissidents and Western leaders put at over 15,000.French President Francois Hollande urged stiffer sanctions against Assad and more support for the rebels at the start of a meeting of Western and Arab states who back the uprising.