Russia unleashed deadly rocket attacks that hit critical infrastructure and residential buildings in 10 regions of Ukraine, the country's president said Thursday.

North Korea last week issued a veiled threat to resume testing nuclear explosives and long-range missiles targeting the U.S.

The move has raised questions about the sincerity of Pyongyang's recent offer for talks with South Korea.

The Biden administration is in the final stages of reviewing its North Korea policy, and sees the recent test as on the "low end" of a "familiar menu of provocations."