The Kerch Strait, which connects the Black Sea and the Sea of Azov, was closed to civilian ships (Picture: Viktor Korotaev/Kommersant/Sipa USA/PA).
Ukraine's president has urged NATO to deploy naval ships to the Sea of Azov amid a stand-off with Russia.
Petro Poroshenko made the call in an interview with the German daily Bild, saying: "We hope that states within NATO are now ready to relocate naval ships to the Sea of Azov in order to assist Ukraine and provide security."
In Sunday's confrontation, the Russian coastguard fired on and seized three Ukrainian vessels trying to pass from the Black Sea into the Sea of Azov through the Kerch Strait, between Russia's mainland and the Crimean peninsula it annexed from Ukraine.
Ukraine insisted that its vessels were operating in line with international maritime rules, while Russia said they had failed to get permission to pass.
'UK wants to do more to help Ukraine'
Defence Secretary Gavin Williamson recently announced he was to commit more troops to Ukraine as well as send HMS Echo, a hydrographic survey ship, to the Black Sea.
“Well, what we announced earlier on this year is that we’re actually increasing the number of people, actually giving that support and training to the Ukrainians," Williamson told Forces News.
"And that is something that’s been incredibly valued by the Ukrainian Government. And we’re seeing that step up over the next year in terms of Operation Orbital.
"But what we’ve been doing there is incredibly valued but we’ve recognised that we want to help more. That’s why we’re doing more.”
The Ministry of Defence said the vessel's presence aimed to "demonstrate the UK's support to ensuring freedom of navigation".
Former First Sea Lord, Lord West, this week said sending a Royal Navy survey ship to Ukraine as "things are hotting up" with Russia is "not a clever idea" and that it would be better to deploy a Type 45 destroyer, which would be "able to look after itself".