Russia launched a "massive" attack on several Ukrainian cities overnight on Monday, President Volodymyr Zelensky has said, a day after he warned of strikes over the Christmas period.

The barrage struck homes and the power grid in 13 regions of Ukraine, causing widespread outages in bitter temperatures, Ukrainian President Volodymyr Zelensky said.

A Russian missile strike on port infrastructure in Odesa in southern Ukraine killed eight people and wounded 27, Ukraine's emergency service said Saturday, as a a Kremlin envoy was set to travel to Florida for talks on a U.S.-proposed plan to end the nearly four-year war.

Air raid alerts were issued across the country, including in Kyiv, where one person was killed. Others were killed in Khmelnytskyy, western Ukraine, and the central Zhytomyr region.

WhatsApp criticised restrictions to its service in Russia on Tuesday, accusing the authorities of trying to deprive more than 100 million Russians of the right to private communications before the holiday season.

The move comes days after a deal with Washington that lifted U.S. sanctions against the Belarusian potash industries, a key source of export earnings.

Peace talks between Russia and Ukraine reportedly proceed "constructively" in Florida even as deadly missile strike hits Odesa, killing eight people.

For countries like Poland, having eyes on and under the Baltic is a pressing matter of national security. The sea teems with telecoms and energy infrastructure. A natural-gas pipeline, the Balticconnector,