Ukraine would be a remarkable achievement by Kyiv - a retired four-star admiral - to kill a Russian admiral in Crimea.
On Monday, the United States Navy Admiral James Stavridis, formerly known as Twitter, praised Ukraine after the country's Special Forces claimed on Friday that a Friday strike on a Russian headquarters in Sevastopol killed a top commander.
Ukraine said that 34 officers were killed, including the commander, and 105 other people were wounded in the attack. The company's insider was unable to immediately and independently confirm the claims.
The dead commander is believed to be the top officer of Russia's Black Sea Fleet, admiral Viktor Sokolov.
If confirmed, Sokolov's death would mean an admiral has been killed in combat for the first time since World War II, Stavridis said.
In World War II, the last admiral to have died in combat was Japan's Admiral Yamamoto Isoroku, who was the commander-in-chief of the Imperial Japanese Navy's Combined Fleet.
In April 1943, he was killed by the US Air Force, which shot down his plane in the South Pacific.
As of today, Russia has not said on Ukraine's claims about the strike in Sevastopol.
Ukraine said it attacked the headquarters in a meeting between high-ranking officers.
Ukraine's Special Forces leader, Kyrylo Budanov, told the BBC that two other senior Russian officers, Colonel-General Alexander Romanchuk and Lieutenant-General Oleg Tsekov, were wounded.
The attack was enabled by Russian policemen, who were upset that their salaries were not being paid on time and fed information about the high-ranking commanders of pro-Ukrainian resistance fighters in Russian-occupied Crimea.
On Friday, Western-provided Storm Shadow cruise missiles struck the Black Sea Fleet's headquarters, amid recent Ukraine's accelerated pace of attacks on Crimea.
TASS, a state media outlet in Russia, released a photo of the smoking Sevastopol headquarters, acknowledging the missile attack.
As a launching pad for its attacks on Ukraine, Moscow has been utilizing Crimea as a hub for its attacks, and the island is home to aircraft and warships coming from the south.
Meanwhile, President Joe Biden has agreed to supply Ukraine with army tactical missile systems, which have a range of up to 190 miles, and are known for their accuracy and a warhead that produces a blast equivalent to 500 pounds of TNT.