A Ukrainian intelligence agency says its military has killed Major General Vitaly Gerasimov, a high-ranking Russian official who received military decorations for his role in forcibly taking Crimea from Ukraine in 2014.

Ukraine’s Chief Directorate of Intelligence of the Defense Ministry said in social mediaon Monday that military forces killed Gerasimov while defending Kharkiv, a city in the northeastern part of the country. The announcement came the same day Ukrainian President Volodymyr Zelensky publicly praised the resolve of his army, saying that demoralized Russian forces had badly underestimated his troops.

In addition to Vitaly, “a number of senior officers of the Russian army were also killed and wounded,” according to the directorate. The intelligence agency also said it has received information that the Russian military is having “significant” problems with communication and “with the evacuation of their broken units.”

If confirmed, Gerasimov would be the second Russian general killed by Ukrainian forces after Russian Major General Andrey Sukhovetskiy died in combat last week.

Russian state newspaper Pravda also reported on the death of Gerasimov. A Russian military spokesperson told the paper that the “evacuation of units and units that suffered losses in the fighting is being delayed.”

Christo Grozev, executive director of investigative journalism outfit Bellingcat, said in a tweet that it had confirmed Gerasimov’s death. In another tweet, Grozev said Ukrainian forces intercepted a phone call from a Russian officer who called his superior to report Gerasimov’s death. The Russian officer said they had lost all secure communications after their cryptophone system stopped working, according to Grozev.

“Russia, if you’re listening: delete your army,” Grozev said in a tweet.

According to Ukraine’s military intelligence agency, Gerasimov was a Russian military commander, chief of staff and first deputy commander of the 41st Army of the Central Military District of Russia. He was also a veteran of the Second Chechen War, where Russian military forces subdued separatists in the north Caucasus in the first decade of the 2000s.

Notably, Gerasimov was given a medal “for the return of Crimea,” a reference to his role in Russia’s annexation of the Black Sea peninsula in 2014 while Ukraine was enthralled in political upheaval. The annexation was widely condemned by Western powers.

The General Staff of the Armed Forces of Ukraine said on social media Monday that it had stopped multiple advances by Russian forces.

“In general, the moral and psychological state of the enemy is low,” reads the post. “He is demoralized due to heavy losses in manpower and military equipment, in some areas it is deserting.”