Russia-Ukraine updates: US sanctions Russian military shipbuilder, diamond miner

At least 31 Russian attacks have been against Ukraine health care facilities, medical staff and ambulances, according to a joint statement Sunday from the World Health Organization, the United Nations and UNICEF.

“Today, we call for an immediate cessation of all attacks on health care in Ukraine. These horrific attacks are killing and causing serious injuries to patients and health workers, destroying vital health infrastructure and forcing thousands to forgo accessing health services despite catastrophic needs," the statement reads.

WHO's surveillance system for the attacks verified that at least 24 health care facilities have been damaged or destroyed. WHO said it has also verified that five ambulances have been destroyed in attacks.

The attacks on health care targets have caused at least 12 deaths and 34 injuries since the Russian invasion began, according to the statement.

Oxygen and other medical supplies, including those used for the management of pregnancy complications, "are running dangerously low," the statement said.

“For example, more than 4,300 births have occurred in Ukraine since the start of the war and 80,000 Ukrainian women are expected to give birth in the next three months," the organizations said.

White House national security advisor Jake Sullivan is scheduled to meet with Chinese foreign policy adviser Yang Jiechi in Rome on Monday, the first in-person, high-level talks between the two countries since Russia launched its invasion of Ukraine, an NSA spokesperson said on Sunday.

The Biden administration has been urging Beijing to use its influence with Moscow to condemn its war.

"The two sides will discuss ongoing efforts to manage the competition between our two countries and discuss the impact of Russia's war against Ukraine on regional and global security," NSA spokesperson Emily Horne said in a statement.

Luigi Mattiolo, diplomatic adviser to Italian Prime Minister Mario Draghi, and Sullivan are also scheduled to meet in Rome “to continue coordinating a strong, united international response to President Putin’s war of choice," Horne said.

-ABC News' Justin Gomez

Almost 13,000 Russian soldiers have been killed since the start of the invasion of Ukraine, President Volodymyr Zelenskyy said on Sunday.

In a short self-shot video address, Zelenskyy also said Russia had lost 1,000 military vehicles, 74 fighter jets and 86 helicopters. It was not immediately possible for ABC News to verify the figures.

Zelenskyy added that a convoy of humanitarian aid was about 50 miles away from the besieged city of Mariupol in southeast Ukraine. He accused the Russians of blocking Orthodox priests who were accompanying the aid, which he said contains "100 tons of the most necessary things that Ukraine sent to its citizens."

"We have already evacuated almost 125,000 people to the safe territory through humanitarian corridors," said Zelenskyy of the situation in Mariupol.

The Mariupol City Council claimed Sunday that 2,187 civilians in the city have been killed since the invasion started on Feb. 24 and that Russia had dropped 100 bombs on Mariupol.

The latest information from the United Nations Human Rights Council shows that 579 civilians have been confirmed killed in Ukraine since the start of the invasion and another 1,002 have been injured.

-ABC News' Christine Theodorou

Pope Francis issued a strong condemnation of Russia's invasion of Ukraine during his Sunday Mass, describing Russian strikes on children's hospitals and civilians as barbaric.

"In the name of God, I ask, stop this massacre," the pope said, calling the Russian invasion an "unacceptable armed aggression."

Speaking at the Vatican, Pope Francis added, "God is the God only of peace, not of war, and those who support violence profane his name."