Ukraine has barred dozens of reporters including three BBC journalists from entering the country as an unspecified security threat.

President Petro Poroshenko signed a sanctions list barring nearly 300 individuals from entering Ukraine.

The decree, published on the president's website, said the three BBC journalists - two Britons and a Russian - and other reporters and media executives presented an unspecified "threat to national interests, national security, sovereignty or territorial integrity".

It did not specify why the BBC was singled out but a spokesman for the president said the Ukrainian Security Service would give an explanation later.

Ukraine has barred entry to Russian journalists in the past, accusing them of inciting unrest in Russian-speaking eastern Ukraine.

The British correspondents are Steve Rosenberg and producer Emma Wells, and the Russian BBC journalist is cameraman Anton Chicherov.

This is the first sanctions list against Russian and foreign individuals that Kiev has introduced since a conflict broke out in April last year in eastern Ukraine, claiming more than 8,000 lives so far.

Also on the list of banned journalists are Antonio Pampliega and Angel Sastre, two Spanish reporters who disappeared in Syria in July and are believed to have been kidnapped by the Islamic State group, and two reporters for Russian news agencies in South Africa and Turkey with no clear links to Ukraine.

Mr Poroshenko said in a statement accompanying the list that the sanctions were introduced against people and companies "linked to the annexation of Crimea and aggression in Donbass" in eastern Ukraine.

Most of the people on the sanctions lists are Russian politicians and political activists who have called for the annexation of Crimea and advocated greater Russian involvement in eastern Ukraine.

BBC foreign editor Andrew Roy described the ban as "a shameful attack on media freedom".

"These sanctions are completely inappropriate and inexplicable measures to take against BBC journalists who are reporting the situation in Ukraine impartially and objectively, and we call on the Ukrainian government to remove their names from this list immediately," he said.

The New York-based Committee to Protect Journalists said in a statement that it was "dismayed" by Mr Poroshenko's actions.

"While the government may not like or agree with the coverage, labelling journalists a potential threat to national security is not an appropriate response," said the committee's Europe and Central Asia programme co-ordinator Nina Ognianova.