US intelligence believes Russia has ordered Ukraine invasion - reports

US intelligence has detected evidence that Russian troops amassed close to the border with Ukraine have received actual orders to proceed with an invasion, according to news reports.

CBS News was the first to report on Sunday that the Kremlin had given the green light to commanders among the more than 150,000 troops in potential attack positions.

"Commanders on the ground are making specific plans for how they would manoeuvre in their sector of the battlefield," Face the Nation reported.

The New York Times also said the Kremlin had ordered an invasion. That intelligence prompted Joe Biden to say this week that the Russian president Vladimir Putin had decided to go ahead with an attack, the newspaper said.

Antony Blinken, the US secretary of state, told CBS the Biden administration remains convinced that Russia is pressing ahead with attack plans.

"As President Biden said, everything we are seeing tells us that the decision we believe President Putin has made to invade is moving forward," he said.

Pressed for details of why the US continues to believe an invasion is imminent despite repeated Russian denials, Blinken pointed to what he called "provocations" and "false flag operations" that could be used as justification for such a move.