Kerry Says U.S. 'on Verge' of Ending Syria Talks with Russia

U.S. Secretary of State John Kerry warned Thursday that Washington was on the brink of ending its talks with Russia on the Syrian conflict over the assault on Aleppo.

"I think we are on the verge of suspending the discussion because, you know, it's irrational in the context of the kind of bombing taking place, to be sitting there, trying to take things seriously," Kerry said.

"There is no notion or indication of seriousness of purpose with what is taking place right now," he told a conference in the U.S. capital, a day after warning his Russian counterpart Sergei Lavrov he would end talks unless Moscow halts the assault on Aleppo.

Kerry said the United States would pursue other alternatives, "barring some clear indication by the warring parties that they are prepared to consider how to approach this more effectively."

A Kremlin spokesman, Dmitry Peskov, said Moscow would press on with its bombing campaign in Syria, where forces loyal to President Bashar Assad are waging a furious assault on Aleppo's rebel-held eastern sector.

A top U.N. aid official called the situation in Aleppo a "merciless abyss of humanitarian catastrophe," in the latest appeal for a halt to fighting.

Kerry's efforts to broker a ceasefire have come under fire from Republicans who have called for tougher action against Moscow and the Syrian regime.

"It's easy to be critical of diplomatic efforts because it's difficult, but what is the alternative?" said Kerry.

He said United States would defeat the Islamic State militants operating in Syria and Iraq, "but that is different and distinct from involving ourselves directly into the civil war which is the war against Assad."

His comments echoed those of President Barack Obama who insisted on Wednesday that "there is not a scenario in which, absent us deploying large numbers of troops, we can stop a civil war in which both sides are deeply dug in."