Ukraine's state-owned electricity transmission system operator, Ukrenergo, said early Thursday that emergency power outages were in place in "most" Ukrainian regions.

Fighting for control of the strategic hub of Pokrovsk in eastern Ukraine is intensifying, with the Russian Defense Ministry claiming to have eliminated a group of Ukrainian special forces sent to help defend the area.

11 people, including four children, were injured in a Russian overnight attack in the Ukrainian city of Sumy, emergency services said;

Moscow's memo reportedly demanded that Ukraine give up large parts of its territory, cut its troops and scrap plans to join NATO.

Russia has recently used a missile whose secret development once triggered the U.S. withdrawal from a landmark nuclear arms control treaty, sources from Ukraine’s foreign ministry told Reuters. The revelation links a weapon central to Cold War-era security agreements directly to the war in Ukraine.

In a rapid escalation of the nuclear rivalry between the United States and Russia, U.S. President Donald Trump announced that Washington will recommence nuclear-weapons testing.