KYIV, Ukraine, May 18 -- Russia overnight into Sunday launched its most intense drone attack on Ukraine since the beginning of its full-scale invasion in 2022, after the first direct talks between Moscow and Kyiv in years failed to yield a ceasefire.

Russian President Vladimir Putin spurned Ukrainian President Volodymyr Zelenskyy's offer to meet face-to-face in Turkey after he himself proposed direct negotiations - although not at the presidential level - as an alternative to a 30-day ceasefire urged by Ukraine and its Western allies, including the US.

Talks in Istanbul on Friday broke up after less than two hours without a ceasefire, although both sides agreed on exchanging 1,000 prisoners of war each, according to the heads of both de...