Ukraine's defense ministry said late Friday it temporarily lost access to the Sea of Azov as Russian troops tightened control of Mariupol, the main port in the Sea of Azov.
The Ukrainian Defense Ministry said in a statement: "The occupiers have achieved partially successful operations in the Donetsk region, temporarily cutting off Ukraine's access to the Sea of Azov.
In its statement, the ministry did not specify whether Ukrainian troops had regained access to the Sea of Azov.
Russia said on Friday that its troops were "tightening" the ropes surrounding Mariupol, where an estimated 80 percent of the city's homes had been damaged. About 1,000 people may still be trapped in a makeshift bomb shelter beneath a destroyed theater.
Mariupol is strategically located on the coast of the Sea of Azov. Russian President Vladimir Putin launched his "special military operation" on Feb. 24, it has been a target for The Russian military.
The city is located on the route between the Russian-annexed Crimean Peninsula to the west and the donetsk region controlled by pro-Russian separatists to the east.
Russia claimed as early as March 1 that its forces had cut off the Ukrainian army from the Sea of Azov.