White House says Biden spoke with leaders of France, Germany and UK amid developments in Russia

Factbox-Russia's Rostov, seized by rebels, is important commodity hub

Russia turmoil to fuel market volatility, flight to safety

How mercenary revolt has gathered pace in Russia

Turmoil in Russia: reactions from foreign governments

Kyiv says F-16 training for Ukrainian pilots could start in July

Three killed in latest Russian air strikes on Ukraine

Russian mercenary boss Prigozhin in standoff with Russian army amid 'armed mutiny'

Russian mercenary boss vows to avenge alleged army attack; Moscow denies accusation

Ukraine signals main push in counteroffensive is yet to come

Britain is facing a mortgage crisis. There are no easy answers

Top Biden aide to Denmark for international talks on Ukraine