A second round of talks between Russian and Ukrainian negotiators will be held at the previously planned venue in neighboring Belarus on Thursday at around 3 p.m. local time (7 a.m. ET), according to Vladimir Medinsky, head of the Russian delegation and aide to Russian President Vladimir Putin.

"The talks will take place -- we are now in contact with the Ukrainian side -- at the same venue where they were planned, on the territory of the Brest region of Belarus," Medinsky told reporters Thursday, adding that Russian negotiators are "waiting calmly."

"I think the talks will begin at 3 p.m.," he said.

Ukraine's presidential advisor Mykhailo Podolyak from the Ukrainian delegation later posted a photo of himself on his official Twitter account on Thursday, saying they were en route via helicopter to the talks in Belarus

-ABC News' Patrick Reevell and Tanya Stukalova

Russian Foreign Minister Sergey Lavrov wouldn't comment on civilian deaths from Russia's invasion of Ukraine when pressed during an interview Thursday with ABC News' George Stephanopoulos on "Good Morning America."

"I cannot comment," Lavrov said, adding that there are "a great deal" of "conjectures."

Ukraine claimed Thursday to have raised its flag over the town of Bucha, close to the Ukrainian capital where some of the most intense fighting has been taking place in recent days and where Russia's push south on Kyiv appears to have stalled.

A video posted on the official Facebook page of the Ukrainian Armed Forces' ground troops purportedly shows soldiers hoisting the national flag outside Bucha's town hall. The town is just a few miles north of the edge of Kyiv and about 15 miles from the center of the capital. Fighting is reported to be ongoing nearby and, in the video, an explosion can be heard in the distance as they raise the blue and yellow flag.

-ABC News' Yulia Drozd

Ukraine is asking the International Atomic Energy Agency (IAEA) to call on NATO to close access to the airspace over the country's Chernobyl nuclear power plant and the surrounding exclusion zone.

The deserted exclusion zone around the Chernobyl nuclear power plant, where the world's worst nuclear accident took place in 1986, was seized by Russian forces last week.

A joint appeal to the IAEA was signed Wednesday by Ukrainian Energy Minister Herman Galushchenko, Oleh Korikov, head of the State Nuclear Regulatory Inspectorate of Ukraine, and Petro Kotin, head of Ukraine's state nuclear energy company Energoatom.

"The fact of the seizure of the world-famous Chernobyl nuclear power plant has all the hallmarks of an act of nuclear terrorism committed against Chernobyl nuclear facilities and its personnel by Russian military units," they said in the appeal.

-ABC News' Yulia Drozd

The United Nations High Commissioner for Human Rights has "received credible reports of several cases of Russian forces using cluster munitions, including in populated areas," spokesperson Elizabeth Throssell said Friday.

"Due to their wide-area effects, the use of cluster munitions in populated areas is incompatible with international humanitarian law principles," Throssell said.

Throssell added, "We remind Russian authorities that directing attacks against civilians and civilian objects as well as so-called bombardment in towns and villages and other forms of indiscriminate attacks are prohibited under international law and may amount to war crimes."

To date, there have been 26 attacks on health care facilities in Ukraine, killing at least 12 people and injuring 34 people, according to Jašarević. Two of those killed and eight of the injured were healthcare workers.

That number is "shocking," said Throssell.

Throssell and WHO spokesperson Tarik Jašarević declined to pin the blame for all of them on Russia.

This number of attacks includes Wednesday's strike on a children's hospital and maternity ward in Mariupol. On Thursday, Russian officials claimed that the attack was staged, but they first confirmed they bombed it and claimed the hospital was being used by Ukrainian "radicals."

Throssell told reporters that is not true; "It was a functioning hospital," she said.

-ABC News' Conor Finnegan