US won't change nuclear posture after Russia lowers threshold, White House says

By Trevor Hunnicutt and Doina Chiacu

WASHINGTON (Reuters) - The United States was not surprised by Russia lowering its threshold for a nuclear strike and does not plan to adjust its own nuclear posture in response, the White House said on Tuesday.

"As we said earlier this month, we were not surprised by Russia’s announcement that it would update its nuclear doctrine; Russia had been signaling its intent to update its doctrine for several weeks," the White House National Security Council said in a statement.

Russian President Vladimir Putin on Tuesday lowered the threshold for a nuclear strike in response to a broader range of conventional attacks, and Moscow said Ukraine had struck deep inside Russia with U.S.-made ATACMS missiles. A Ukrainian and U.S. official confirmed the strike to Reuters.

"Observing no changes to Russia’s nuclear posture, we have not seen any reason to adjust our own nuclear posture or doctrine in response to Russia’s statements today," the statement said.

It cited Russia's use of North Korean troops in Ukraine, which it called a significant escalation.

The updated Russian nuclear doctrine, establishing a framework for conditions under which Putin could order a strike from the world's biggest nuclear arsenal, was approved by him on Tuesday, according to a published decree.

The doctrine said any attack by a non-nuclear power supported by a nuclear power would be considered a joint attack, and that any attack by one member of a military bloc would be considered an attack by the entire alliance.

Russia has been warning the West for months that if Washington allowed Ukraine to fire U.S., British and French missiles deep into Russia, Moscow would consider those NATO members to be directly involved in the war in Ukraine.

The White House statement said the rhetoric was irresponsible.

Russia's defense ministry has said Ukraine struck Russia's Bryansk region with six missiles, and that air defense systems intercepted five and damaged one.

(Reporting by Trevor Hunnicutt and Doina Chiacu; editing by Jonathan Oatis, William Maclean and Alistair Bell)