Vladimir Putin has signed an update to Russia's nuclear doctrine, coinciding with the 1,000th day of the war in Ukraine. While the doctrine reaffirms nuclear weapons as a last resort to safeguard Russia's sovereignty,

Vladimir Putin on Tuesday signed a decree revising Russia's nuclear doctrine to broaden the basis on which Moscow would consider using nukes, just two days after the U.S. authorized Ukraine to use its longer-range missiles to strike targets in Russia.

U.S. President Joe Biden has cleared Kyiv to use long-range American missiles against military targets inside Russia, U.S. media reported late Sunday, promoting fears of escalating the conflict with nuclear-armed Moscow.