More than 20 Russian aircraft and two coastguard ships have shadowed a British warship sailing near Crimea.
Moscow’s defence ministry said a patrol ship fired warning shots and a jet dropped bombs in the path of HMS Defender as it sailed some 12 miles (19km) off Crimea’s coast.
The UK government rejected Russia’s account of the incident and denied that any warning shots had been fired.
A BBC correspondent on the warship said it was harassed by Russia’s military.
Aircraft could be heard overhead as BBC defence correspondent Jonathan Beale filed a report from the deck of HMS Defender in the Black Sea as it sailed to Georgia.
He described hostile warnings over the radio as the warship’s crew prepared for a possible confrontation.
Our correspondent, who had been invited on board the ship before the incident happened, saw more than 20 aircraft overhead and two Russian coastguard boats which at times were just 100m (328ft) away.
HMS Defender was sailing from Odessa in southern Ukraine to Georgia. To get there, it passed south of the Crimea peninsula, which Russia annexed from Ukraine in 2014 in a move that has not been recognised internationally.
While Moscow claims the peninsula and its waters are Russian territory, the UK says HMS Defender was passing through Ukrainian waters in a commonly used and internationally recognised transit route.
A source told BBC diplomatic correspondent James Landale that the Defender was not there to pick a fight but to make a point – to assert its right to freedom of navigation in international waters.
Russia’s defence ministry said the “dangerous actions” of the navy ship entering its waters were a “gross violation” of the UN Convention’s sea laws, and called for the crew to be investigated.
A later tweet from the Russian embassy in the UK said: “HMS Defender turns HMS Provocateur and violates Russian border. Not exactly a ‘routine’ transit, is it?”
UK Defence Secretary Ben Wallace added: “As is routine, Russian vessels shadowed [the ship’s] passage and she was made aware of training exercises in her wider vicinity.”
The British ambassador was summoned to the Russian foreign ministry in Moscow, and met officials on Wednesday afternoon.
Headline photo:- Sukhoi Su-35 jet fighters of the Sokoly Rossii (Falcons of Russia) aerobatic team fly in formation during a rehearsal for an airshow in Krasnoyarsk, Russia