Biden will meet Putin 'at any time' to defuse Ukraine crisis: Blinken

US president Joe Biden is willing to meet Russia's Vladimir Putin "at any time" to defuse Ukraine war tensions, his top diplomat said Sunday, warning Russia appeared on the verge of invading its neighbor.

In a rapid-fire round of US talk shows, secretary of state Antony Blinken told CNN "everything we're seeing suggests that this is dead serious, that we are on the brink of an invasion."

"But until the tanks are actually rolling and the planes are flying, we will use every opportunity and every minute we have to see if diplomacy can still dissuade president Putin from carrying this forward."

Blinken told CBS's "Face the Nation" Biden has made "very clear that he's prepared to meet President Putin at any time, in any format, if that can help prevent a war."