Jake Sullivan, a White House national security advisor, held secret talks with senior Russian officials to warn them against using nuclear weapons.

US and allied officials told the publication that Sullivan had held talks with two Russians, one of which was a foreign policy adviser to the Russian president.

The US wanted to prevent the war in Ukraine from getting worse so that Russia wouldn't have to use its nuclear weapons.

Concerns that Russia could use tactical nuclear weapons in Ukraine were raised during the talks.

Putin warned the West that he was not bluffing when he said he would use nuclear weapons to defend Russia.

According to the New York Times, Russian military leaders discussed using them.

Russia's military was forced to retreat in the east of the country after being forced to do so by Ukraine.

The US and other intelligence agencies say they have not seen any signs of the military getting ready to use nuclear weapons.

US and Russian military officials have held discussions to avoid miscommunications that could cause the war to spread beyond Ukraine.

Mark Milley, chairman of the joint chiefs of staff, and Valery Gerasimov, chief of the Russian general staff, have been in private communication.

In the aftermath of the invasion, diplomatic relations have been limited, and the last time President Joe Biden and Putin spoke was in February.