Washington, Muharram 2, 1438, Oct 3, 2016, SPA -- The United States suspended Monday its cooperation with Russia on Syria, citing the failure of a ceasefire and Moscow's inability to end the violence, dpa reported. "This is not a decision that was taken lightly," State Department spokesman John Kirby said in a statement, pointing to extensive negotiations that the US and Russia have conducted thus far in an effort to end the civil war. "Unfortunately, Russia failed to live up to its own commitments ... and was also either unwilling or unable to ensure Syrian regime adherence to the arrangements to which Moscow agreed." A high-ranking source in the Russian Foreign Ministry told the Interfax news agency the US decision "evokes disappointment." The unidentified source said the ministry must further analyse the US decision before officially responding. The US statement cites Russia and Syria's intensified military attacks against civilian areas, infrastructure and hospitals, including an attack on an aid convoy last month. It said the US woud withdraw personnel that were to have worked to establish a Joint Implementation Center with the Russians, but would continue to use channels to "deconflict conterterrorism operations." US Secretary of State John Kerry threatened last week to end US engagement with Russia on Syria, which further escalated tensions with Moscow over its involvement in the war-ravaged country. Kerry had demanded Russia take "immediate steps" to end a military campaign on the rebel-held section of Aleppo. The move indicated that "everybody's patience with Russias has run out," White House spokesman Josh Earnest said. "What's clear is there is nothing more for the US and Russia to talk about with regards to trying to reach an agreement to end the violence inside of Syria, and that's tragic," Earnest said. -- SPA 22:30 LOCAL TIME 19:30 GMT www.spa.gov.sa/w