The arrival comes after reports the US may send its warship to the Black Sea amid the Kerch Strait tensions. On November 25, Russia detained three Ukrainian Navy ships which breached the Russian maritime border, trying to sail through the Kerch Strait, the entrance into the Sea of Azov.

The UK Royal Navy's survey vessel HMS Echo has entered the Black Sea "for the first time since the Sea of Azov crisis", according to a tweet by the Turkish tracking website Bosphorus Observer.

The media outlet reported the ship was scheduled to remain in the Black Sea for 21 days in line with the Montreux Convention Regarding the Regime of the Straits. The document gives Turkey control over the Bosporus Straits and the Dardanelles and regulates the transit of naval warships.

.@RoyalNavy returns to BlackSea for the first time since the Sea of Azov crisis: Devonport based, Echo class multirole hydrographic & oceanographic survey vessel @HMS_Echo transited Bosphorus. The survey suit consists of EM710MBES, EA600 single beam echo-sounder, towed side sonar pic.twitter.com/0ASjn1Neck — Yörük Işık (@YorukIsik) 17 декабря 2018 г.

HMS Echo is equipped with sonars and sensors for obtaining intelligence data. The vessel also has three six-barrel 7.62mm machine guns, an M134 Minigun as well as two 20mm Erlikon anti-aircraft guns, Bosphorus Observer reported.

Freedom of Navigation in the Black Sea: Built by Appledore Shipbuilders in Bideford, Echo class HMS Echo is armed with 20mm, Mk44 7.62mm guns. HMS Echo entered BlackSea at 18:00GMT, escorted by Turkish Coast Guard TCSG29. She can remain for 21 days according to Montreux Treaty. pic.twitter.com/Vvbl51bgeb — Yörük Işık (@YorukIsik) 17 декабря 2018 г.

HMS Echo's arrival in the Black Sea comes after media reports earlier this month that the US military had allegedly asked the Department of State to notify the Turkish government about its intent to sail a warship into the Black Sea.

The move comes in response to a naval incident in the Kerch Strait on November 25, when Russian detained three Ukrainian Navy ships — gunboats Berdyansk and Nikopol, as well as tugboat Yanu Kapu — after they breached the Russian maritime border, attempting to sail through the Kerch Strait, the entrance into the Sea of Azov.

READ MORE: Trump: Kerch Strait Incident 'Sole Reason' for Cancelling G20 Talks With Putin

Shortly after the incident, Ukrainian President Petro Poroshenko decreed martial law for three months in several regions of the country bordering Russia, as well as the coast of the Black Sea and the Sea of Azov.

The United States urged Russia to release the sailors and return the seized vessels to Ukraine. President Donald Trump decided to call off a meeting with Russian President Vladimir Putin during the G20 summit in Argentina after receiving a report on the Kerch Incident.

Russian President Vladimir Putin, for his part, described the incident as a "provocation" used as a pretext to introduce martial law in Ukraine. President Putin suggested it could be connected with Poroshenko's low approval ratings with the March 2019 presidential election looming in Ukraine.