If the West wants to fight for Ukraine on the battlefield, Russia is prepared for it, acting Russian foreign minister Sergei Lavrov was quoted as saying by the state-run RIA new agency on Monday.
The Kremlin said last week that sending Nato troops into Ukraine would potentially be extremely dangerous, and that Moscow was closely watching a Ukrainian petition calling for such an intervention.
Meanwhile, the Ukrainian commander responsible for the northeastern Kharkiv frontline was replaced during the Russian offensive, a military spokesperson said on Monday.
Nazar Voloshyn told RBC-Ukraine media that the decision to appoint brigadier general Mykhailo Drapatyi to the position was taken on May 11th. He gave no reason.
Russian troops launched an offensive at the region's border early on May 10th.