Tensions remain high in Crimea ahead of a proposed referendum on March 16, which could see the Ukrainian region become part of Russia.

Ukraine's interim prime minister has warned the Crimean parliament that "no-one in the civilised world" will recognise the vote, which has the support of Moscow.

The BBC's Ben Brown visited a Ukrainian naval base in Sevastopol, Crimea, that had been surrounded by what appeared to be Russian forces.

He spoke to Lt Cdr Olaxander Yesin, who said that he was still following orders from Kiev and that those on base would not surrender unless ordered to do so by their commanding officers.