KIEV (AFP/Reuters) - Crimean authorities have released the head of the Ukrainian navy whom they had seized during a raid on a base in the rebel peninsula, Ukraine's acting president said.

"Rear admiral Sergiy Gayduk was released tonight along with all the other civilian hostages... seized by Russian soldiers and members of the self-declared authorities of Crimea" on Wednesday, Mr Oleksandr Turchynov was quoted as saying in a statement by the Interfax news agency.

A Ukrainian military spokesman said Admiral Serhiy Haiduk had been driven away from a navy compound in Russian-controlled Crimea by what appeared to be Russian special forces.

Russian Defence Minister Sergei Shoigu asked the authorities in Crimea on Thursday to free the detained hostages and allow them safe passage out of the region.