US envoy to Syria Robert Ford, an open critic of President Bashar Al-Assad's crackdown on political dissent, has left Syria indefinitely for security reasons, an embassy official said yesterday. The US State Department confirmed that Ford was pulled out, citing "credible threats" against his safety. Meanwhile six civilians were reportedly killed yesterday, five of them in the flashpoint central city of Homs as the army pressed its brutal suppression of political protest that has infuriated the in ternational community. Ambassador Robert Ford is on leave indefinitely. Washington decided to give him the leave out of concerns about his personal safety," the embassy official told AFP, speaking on condition of anonymity. Washington's concerns emerged "following critical newspaper articles", said the official, without elaborating. Ford has come in for heavy criticism by regime supporters in Damascus who have accused him of helping incite violence in the country, where according to UN estimates more than 3,000 people have been killed since mid-March. The ambassador has also angered the regime by visiting protest hubs outside the capital in a show of solidarity with pro-democracy demonstrators. The State Department said Ford was brought back to Washington because of "credible threats against his personal safety in Syria". It said Washington hoped the Syrian government would end its "incitement campaign" against Ford who, he said, "has worked diligently to deliver our message and be our eyes on the ground". The US Senate earlier this month unanimously confirmed Ford's appointment as ambassador to Syria, calling it "a tough message" to Assad and a sign of US "solidarity with the Syrian people". "Despite even being physically attacked and assaulted by the regime's goons, Ford continues courageously to visit cities under military siege and speak truth to power," US Senator John Kerry said at the time. Washington has repeatedly urged the UN Security Council and the international community to step up pressure on Syria over its bloody response to opposition to the government in Damascus. On Sunday, the European Union, which has issued several rounds of sanctions against Assad's regime, Syrian banks and the oil sector, warned of new measures if Damascus fails to halt violence against dissenters. A rights watchdog said Syrian forces in Homs yesterday raked several neighbourhoods with heavy artillery fire. The Syrian Observatory for Human Rights said at least three of the five people killed in Homs yesterday were shot dead by security forces and pro-regime militiamen. It said the sixth person was killed when a rocket-propelled grenade fired by troops in the northwestern province of Idlib hit his car. Meanwhile the pro-government Al-Watan newspaper said Assad will "soon" chair a "conference on national dialogue in order to put an end to the crisis in Syria". The report comes as an Arab League delegation is due to visit Damascus tomorrow in a new attempt to defuse the tension and prod talks between Assad's regime and the opposition. Assad's supporters late last month tried to attack Ford and embassy staff as they visited a Syrian opposition leader in Damascus. Toner said at the time the pro-regime demonstrators seriously damaged US vehicles and pelted the visitors with tomatoes but did not hurt Ford or his staff. Following the incident, the United States summoned the Syrian ambassador to Washington, Imad Mustapha, and according to State Department spokeswoman Victoria Nuland, he was "read the riot act".