MOSCOW: Russia is sending more warplanes to Syria to ramp up its air campaign, a Russian newspaper reported on Friday, as the United States said diplomacy to halt the violence was on life support but not dead yet. Fighting continued to intensify a week into a new Russian-backed Syrian government offensive to capture rebel-held eastern Aleppo and crush the last urban stronghold of a revolt against Syrian President Bashar al-Assad that began in 2011. Moscow and Assad spurned a US-Russian brokered ceasefire agreed to this month and launched attacks on rebel-held areas in Aleppo in potentially the most decisive battle in the Syrian civil war. US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov spoke by telephone for a third straight day, with the top Russian diplomat saying Moscow was ready to consider more ways to normalise the situation in Aleppo. But Lavrov criticised Washington’s failure to separate moderate rebel groups from those the Russians call terrorists, which had allowed forces led by the group formerly known as the Nusra front to violate the US-Russian truce agreed on Sept. 9. The United States made clear on Friday that it would not, at least for now, carry through on the threat it made on Wednesday to halt the diplomacy if Russia did not take immediate steps to halt the violence. This is on life support, but it’s not flat-lined yet, State Department spokesman Mark Toner told reporters. We have seen enough that we don’t want to definitively close the door yet. In a 40-minute discussion with Syrians, diplomats and others on the sidelines of the United Nations General Assembly meeting in New York last week, Kerry said the administration had failed to make any threat of military force that give him leverage with Russia. I think you’re looking at three people, four people in the administration who have all argued for use of force, and I lost the argument, Kerry told the group, according to a recording of the session obtained by The New York Times.