Putin orders nuclear test preparations after Trump announces U.S. will resume testing. Russia vows proportionate response to American nuclear program moves.

Russia said on Saturday that its forces continued to advance in grinding battles around the key towns of Pokrovsk and Kupiansk, and had captured a tiny village in eastern Ukraine.

The Kremlin is focusing its fire on Pokrovsk, a gateway to the Donetsk region, which Russia’s president, Vladimir V. Putin, has long coveted.

Ukrainian long-range drones attacked an industrial plant around 1,300 kilometers (800 miles) inside Russia, local officials said Tuesday, while Ukraine’s army remained locked in an intense battle to hold back a Russian push on the key city of Pokrovsk in the eastern Donetsk region.

The battle for Pokrovsk - on a big road and rail artery in the Donetsk region - has been going on for well over a year.

By Sarah Marsh BERLIN (Reuters) -Two lawmakers from the far-right Alternative for Germany travel next week to Russia while under fire from opponents for the party's ties to the Kremlin and accusations - strongly denied - that it could be passing on sensitive military information.

The devastated city -- which was home to some 60,000 people before Russia's February 2022 full-scale invasion -- has become a key focus of the Kremlin's yearslong push to capture all of Ukraine's eastern Donetsk Oblast, which along with neighboring Luhansk Oblast makes up the Donbas region.

President Cyril Ramaphosa has "ordered an investigation into the circumstances that led to the recruitment of these young men into these seemingly mercenary activities," a government spokesman said. The statement did not say which side of the conflict the South Africans were fighting for.