Kiev forces make progress in key city of Mariupol
Ukrainian forces seized the rebel-held city hall in the eastern port city of Mariupol overnight, driving out pro-Russian activists, then withdrew, making no attempt to hold onto the building.
Ukraine's Channel 5 television said earlier the Ukrainian National Guard had seized the administrative centre in Mariupol, a mainly Russian-speaking city of half a million and key component in the self-declared breakaway People's Republic of Donetsk that will hold a referendum on secession this weekend.
But witnesses said the soldiers left after smashing furniture and office equipment. The smell of tear gas hung in the air inside the building which was largely empty in the morning, except for activists in gas masks clearing debris.
It was at least the second such short-lived change of hands - pro-Kiev militants mounted an overnight raid on April 24, forcing pro-Moscow activists out, but only for the day.
Kiev has declared Sunday's activist-run referendum in the regions of Donetsk and Luhansk illegal, and fears it is but a first step to Moscow annexing the regions as it did Ukraine's Crimea peninsula two months ago.