Feb 3 (Reuters) - Russian forces attacked Ukraine's capital of Kyiv, its second largest city of Kharkiv and other centres early on Tuesday, officials said, triggering fires and dealing new blows to energy infrastructure.

U.S. envoy Steve Witkoff calls Ukraine and Russia's exchange of 314 prisoners "tangible progress," but acknowledges a lot of work left to end the war.

Kyiv is trying to hammer out concessions from Moscow and iron-clad security guarantees from its allies to end the war as Russia appears to dig in on territorial claims.

SpaceX has introduced new restrictions to block Russian forces from accessing Starlink in Ukraine, a move Ukrainian officials describe as a major setback for Moscow’s battlefield operations.

Emergency power cuts have hit several Ukrainian cities and neighboring Moldova. Ukraine’s Energy Minister says a technical malfunction caused the outages, affecting power lines between Ukraine and Moldova.

It’s unclear what effect the change will have on Russia’s ability to wage war, but Russian military bloggers said troops were experiencing internet outages that hampered frontline communications.

Whitkoff says ‘significant work remains’ as second day of US-led peace talks in Abu Dhabi concludes: What we know on day 1,444

KYIV, Ukraine (AP) — The U.S. and Russia agreed on Thursday to reestablish high level military-to-military dialogue following a meeting between senior Russian and American military officials in Abu Dhabi, the United States European Command said in a statement.

The prime minister's visit comes as Ukraine faces rolling blackouts following repeated Russian strikes on power facilities, prompting Kyiv to declare a state of emergency on Jan. 14. "At this critical time, Ukraine cannot be left all alone," Tusk said ahead of the visit.