WASHINGTON (AFP) - US President Barack Obama joined key British and Saudi allies Saturday in demanding that the Syrian regime "immediately" halt its brutal crackdown on protesters. During a telephone conversation, Obama and Saudi King Abdullah expressed their "shared, deep concerns about the Syrian government's use of violence against its citizens," the White House said in a statement. "They agreed that the Syrian regime's brutal campaign of violence against the Syrian people must end immediately." Kuwait and Bahrain followed suit this week, while the Gulf Cooperation Council and the Arab League condemned the violence that has left more than 2,150 people dead. Turkey has also expressed growing impatience with Assad's scorched earth policy, as has Russia. In a separate phone call, Obama and UK PM David Cameron also agreed on the need for an "immediate" end to the bloodshed. They reiterated "their deep concern about the Syrian government's use of violence against civilians and their belief that the Syrian people's legitimate demands for a transition to democracy should be met." Obama vowed to remain in close contact with the British and Saudi leaders over developments in Syria, where Assad's security forces have engaged in a weeks-long campaign of violence, using automatic gunfire on civilians protesting against the regime. Rights activists say the latest casualties included at least three people killed as Syrian troops pounded Latakia and raided other towns. Military vehicles, including tanks and armoured personnel carriers, converged on Ramleh during a "large demonstration calling for the fall of Assad's regime," according to the watchdog. OIC chief Ekmeleddin Ihsanoglu meanwhile urged Syrian leaders to "exercise utmost restraint through immediate cessation of the use of force to suppress people's demonstrations," an OIC statement said.