The United States said Tuesday it has "credible information" that Russia may use "chemical agents" in its offensive to take the besieged Ukrainian city of Mariupol, reigniting concerns about the use of such prohibited weapons.

While the West and Kyiv have been warning Moscow since the start of its invasion on Feb. 24 against any use of chemical

The United States has "credible information" that Russia "may use... chemical agents" in its offensive to take the besieged Ukrainian city of Mariupol, U.S. Secretary of State Antony Blinken said Tuesday.

The top U.S. diplomat said he was "not in a position to confirm" recent allegations that Moscow used chemical weapons in Mariupol, a strategic

Ukrainian authorities on Tuesday announced they had captured a prominent pro-Kremlin tycoon who escaped from house arrest after Russia's invasion.

President Volodymyr Zelensky posted a picture online of a disheveled-looking Viktor Medvedchuk with his hands in cuffs and dressed in a Ukrainian army uniform.

"A special operation was carried out by the

Russian troops on Tuesday intensified their campaign to take the port city of Mariupol, part of an anticipated massive onslaught across eastern Ukraine, as President Vladimir Putin made a defiant case for the war on Russia's neighbor.

Moscow is believed to be trying to connect occupied Crimea with Russian-backed separatist territories Donetsk and