Pro-Russian separatists in Ukraine are reported to be regrouping in Donetsk after government forces retook some of their main strongholds.

President Petro Poroshenko said the recapture of the rebels' stronghold of Sloviansk on Saturday was of "huge symbolic importance".

But he warned it was too early for celebrations.

Despite recent losses, the rebels still hold the regional capitals of Donetsk and Luhansk and other key areas.

Sloviansk had been considered a focal point of the rebellion, and was the military centre of the self-declared separatist People's Republic of Donetsk.

But on Saturday, following a night of mortar shelling, rebels left the city in a move apparently orchestrated by the breakaway region's military commander, Igor Strelkov.

President Poroshenko said troops had "liberated Sloviansk from terrorists", and that it was "the start of a turning point in the fight against the militants".

The rebels said they had staged a "tactical retreat" to Donetsk, the main city in the region.

Ukrainian Interior Minister Arsen Avakov said some rebels had surrendered or were trying to escape by blending in with the civilian population.

But those that remained appeared to be heading next for the town of Horlivka, he said on his Facebook page, and were being confronted on the road by government troops.

BBC