The outskirts of Ukraine's port city of Mariupol came under heavy fire and hundreds of explosions have been observed there, a diplomatic source told Reuters on Thursday, as Ukrainian forces battled Russian invaders on three sides.
Moscow has mounted an assault by land, sea and air in the biggest attack on a European state since World War Two.
(Reporting by Anton Zverev; Writing by Alexander Marrow; Editing by Hugh Lawson)
