Ukrainian President Volodymyr Zelenskyy also urged NATO leaders to immediately approve the uncontested parts of Ukraine for membership.

Ukrainian Foreign Minister Andrii Sybiha has urged his NATO counterparts to issue an invitation during a meeting in Brussels next week to Kyiv to join the Western military alliance, according to the text of a letter seen by Reuters on Friday.

"We believe that the invitation should be extended at this stage," Foreign Minister Andrii Sybiha wrote in a letter to his NATO counterparts.

Ukrainian officials say Russia has conducted a “massive” attack against Ukraine’s energy infrastructure, firing nearly 200 missiles and drones and leaving more than a million households without power

Russian forces have launched a major assault on Ukraine, firing missiles on cities and military targets. The invasion by land, air and sea began after a pre-dawn TV address where Russian President Vladimir Putin demanded that Ukraine's military lay down its arms.