Ukrainian armed forces on Friday have now identified a large Russian landing ship that they said they destroyed at the port of Berdiansk in southern Ukraine the day before.
The port, which had recently been occupied by Russian forces with several Russian warships in dock, was rocked by a series of heavy explosions soon after dawn on Thursday.
Social media videos showed fires raging at the dockside, with a series of secondary explosions reverberating across the city.
The Ukrainian armed forces on Friday named the ship as the "Saratov." In earlier reporting, the ship was named as the "Orsk."
A day before the ship's explosion, a lengthy news report on the Russian state-controlled international TV network, RT, had featured what they said was a Russian warship named "Orsk" which is the class of landing vessel as the "Saratov" — a class known to NATO as "alligator."
The Russian Ministry of Defense has made no official comment about the explosion.
In a statement, the Ukrainian armed forces said: "In the Azov operational zone, according to updated information, a large landing ship "Saratov" was destroyed during the attack on the occupied Berdiansk port. Large landing ships "Caesar Kunikov" and "Novocherkassk" were [also] damaged. Other losses of the enemy are being clarified."
Several Russian ships had been unloading military equipment at Berdiansk in recent days, according to reports from the port by Russian media outlets.
The United States said that Ukraine likely did conduct a successful attack against Russian ships in Berdiansk, according to a defense official, though it is unclear what type of weapon or weapons were used in the attack. It echoes a similar statement from the British Ministry of Defence, which said that Ukrainian forces have attacked "high value targets" in Russian-occupied areas of Ukraine, including a landing ship and ammunition depots at Berdiansk.
Analysis of videos uploaded on Thursday showed that one Russian naval vessel left the port soon after the explosions.
RT is state-controlled Russian media and is considered a mouthpiece for the Kremlin. It has been under international sanctions since the beginning of the month.
This story has been updated with new information from Ukrainian officials.
CNN's Andrew Carey, Tim Lister, Celine Alkhaldi, Olga Voitovych and Gianluca Mezzofiore contributed reporting to this post.