Ukraine's president says a new prisoner exchange with Russia is ongoing and will take days, as both sides continue launching hundreds of attack drones.

Russia and Ukraine started a major prisoner exchange on Monday after days of wrangling cast doubt over the only concrete result of peace talks last week in Turkey.

(Reuters) -Ukrainian President Volodymyr Zelenskiy vowed on Sunday to press on with prisoner exchanges with Russia and said any failure by Moscow to uphold humanitarian accords cast doubt over U.S. and other efforts to end the more than three-year-old conflict.

The Russian Ministry of Defense said soldiers have advanced into the Dnipropetrovsk region in south-central Ukraine.

Reuters, the news and media division of Thomson Reuters, is the world’s largest multimedia news provider, reaching billions of people worldwide every day. Reuters provides business, financial, national and international news to professionals via desktop terminals, the world's media organizations, industry events and directly to consumers.

Russia claimed Sunday that its forces are for the first time pushing into the central Ukrainian region of Dnipropetrovsk, an area it has been trying to reach for months, in a move that could create new problems for Kyiv’s much-stretched forces.