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

U.S. Secretary of State Antony Blinken crossed the border into Ukraine Saturday after meeting with Ukrainian Foreign Minister Dmytro Kuleba at the Korczowa Border Crossing Point.

"The entire world stand with Ukraine," Blinken said, and Kuleba added that he hopes Ukrainians will see this as a "clear manifestation that we have friends who literally stand by us."

Blinken said the sanctions imposed so far against Russia are "producing very, very concrete results" and that the pressure will "grow" until this "war of choice is brought to an end."

When asked directly about helping Kuleba with more firepower, Blinken said, "the support for Ukraine not only has been unprecedented, not only is going to continue, it's going to increase."

Kuleba said Ukraine "appreciates" sanctions that have been announced in the last week, but that more economic and political pressure and "necessary weapons," would "save many lives in Ukraine... many sufferings will be avoided."

Kuleba also said that they are “satisfied" with already arranged supplies of anti-tank weapons and ammunition, but that “it’s no secret” they still want fighter jets and air defense systems.

He also thanked the U.S. for sending stingers, and said they were used on Saturday.

"Just today we shot down three Russian attack aircrafts, which were bombing our cities with the use of stingers but we need -- so to say -- big air defense systems to ensure the safety of our skies. If we lose the skies, there will be much, much more blood on the ground,"Kuleba said.

In response to questions about NATO’s refusal to impose a no-fly zone over Ukraine, Kuleba said it’s a "sign of weakness," but stayed optimistic that they will change their minds.

"The time will come," he said.

-ABC News' Conor Finnegan and Justin Gomez