Air defences were engaged in Ukraine's capital of Kyiv on Thursday to repel a Russian drone attack, officials said, and Reuters witness reported explosions in the city while British Prime Minister Keir Starmer was visiting.

Meanwhile, British Prime Minister Keir Starmer signed a "landmark" 100- year partnership agreement with Ukraine during an unannounced visit to Kyiv. Here are the latest developments from Russia's war in Ukraine on January 16,

Russia’s military on Tuesday said it would retaliate against Ukraine after Kyiv attacked Russian regions by firing six US-made ATACMS ballistic missiles, six UK-made Storm Shadow cruise missiles and launching one of the biggest drone attacks to date.

The barrage appeared to be one of the largest recent assaults in Ukraine’s campaign to damage Russia’s war machine on its home territory.

Ukrainian President Volodymyr Zelenskyy warned allies that the defense of his nation is a litmus test for broader Western resolve.

Ukraine carried out one of its largest drone attacks against Russia in this war, striking energy production facilities, weapons storage sites, and other military targets in about a dozen regions across the country,

Ukraine claimed Saturday to have struck one of Russia’s largest oil refineries in a drone attack, starting a fire at the facility more than 700 miles into Russian territory.