Flights are gradually back in the air, but uncertainty on the ground still lingers.

Russian officials cast Ukrainian attacks as 'terrorism' as they urge 'vigilance'.

British officials have raised the national terrorism threat to its second-highest level.

Diplomatic efforts to resolve the conflict have hit an impasse, with a ceasefire in place since April 8.

Attacks on towns on the Black Sea and in central Ukraine kill one, injure several.