BEIRUT (Reuters) - The Syrian government ignored Arab powers moves to halt its crackdown on a pro-democracy uprising on Friday and more opposition supporters and military personnel were killed in unrelenting violence. The Syrian military said 10 personnel, including six pilots, were killed in an attack on an air force base and that the incident proved foreign involvement in the eight-month revolt against President Bashar al-Assads rule. Government forces shot dead at least four demonstrators in the capital Damascus who were appealing for foreign intervention to stop the crackdown, activists said. Two other civilians were killed in raids on their homes, they said. Earlier on Friday, a deadline set by the Arab League for Syria to sign a deal allowing peace monitors into the country expired without any government response. Turkey meanwhile said it could no longer tolerate any more bloodshed. Under the Arab League initiative, Syria agreed to withdraw troops from urban centres, release political prisoners, start a dialogue with the opposition and allow in monitors. The bloodshed did not stop and Arab foreign ministers said in Cairo on Thursday that unless Syria agreed to the monitors, they would consider imposing sanctions including halting flights, curbing trade and stopping deals with the central bank. The League extended the deadline after it expired on Friday , saying they would wait until the days end before deciding what to do. The announcement of the air force attack appeared to be an oblique response. An armed terrorist group undertook an evil assassination plot that martyred six pilots, a technical officer and three other personnel on an air force base between Homs and Palmyra, a military spokesman said on state television. This confirms the involvement of foreign elements and their support of these terrorist operations in an effort to weaken the fighting capabilities of our forces, he said. In neighbouring Turkey, Foreign Minister Ahmet Davutoglu said he hoped the Syrian government would give a positive response to the Arab League plan. If it doesnt, there are steps we can take in consultation with the Arab League, he said. I want to say clearly we have no more tolerance for the bloodshed in Syria.. The stepped-up pressure followed a French proposal for humanitarian corridors to be set up through which food and medicine could be shipped to alleviate civilian suffering. But some a measure of comfort for Assad came from long-time ally Russia, China and other countries, who expressed opposition to sanctions and warned against a foreign military intervention. At the current stage, what is needed is not resolutions, not sanctions, not pressure, but internal Syrian dialogue, Russian Foreign Ministry spokesman Alexander Lukashevich said in Moscow. Lukashevich said Russia supported the Arab Leagues call for a halt to the violence but that radical opposition groups with foreign support shared the blame. Outside military intervention was absolutely unacceptable. After a meeting in Moscow on Thursday, diplomats from Russia, China and the other three emerging-market BRICS countries Brazil, India and South Africa - also warned against foreign intervention without U.N. backing.