The death toll in Ukraine is "thousands higher" than reported, according to a United Nations (U.N.) official.
The head of the U.N. Human Rights Monitoring Mission in Ukraine (HRMMU) in Ukraine, Matilda Bogner, told reporters on Tuesday that the agency is working on estimates.
CIVILIAN CASUALTIES IN UKRAINE SURPASS 7K UNDER RUSSIAN INVASION: UN REPORT
"The actual figures are higher and we are working to corroborate every single incident," she said.
Across the country, the global body has confirmed 3,459 civilian deaths since the beginning of the war.
Bogner called Mariupol the "black hole;" access to the southeastern port has been limited as Russian forces continue their assault.
She also noted that the U.N. had received reports of more than 300 men, women and children being unlawfully killed in Bucha.
The Office of the U.N. High Commissioner for Human Rights (OHCHR) also recorded 3,713 injuries.
BIDEN SAYS HE'S WORRIED PUTIN 'DOESN'T HAVE A WAY OUT' OF UKRAINE WAR
On Tuesday, Ukrainian officials said Russian troops hit the port of Odesa, in what seemed to be an effort to disrupt supply lines and Western weapons shipments.
While Ukrainian fighters remain holed up at Mariupol's Azovstal steel plant, warplanes continued to attack.
The U.N. and Red Cross previously organized a rescue of what some officials said were the last civilians trapped at the plant.
But two officials said Tuesday that about 100 were believed to still be in the complex’s underground tunnels. Others said that was impossible to confirm.
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President Biden said Monday he is concerned that Russian President Vladimir Putin "doesn't have a way out" and will continue his brutal war in an attempt to save face at home.
"I'm trying to figure out what we do about that," he reportedly said.
Fox News' Greg Norman, The Associated Press and Reuters contributed to this report.