Russia's state censor, Roskomnadzor, added Twitter to its list of banned sites in the country on Friday, following a request from the Russian prosecutor general.

Earlier Friday, Roskomnadzor banned Facebook as the Russian government moves to limit dissent over the war in Ukraine.

-ABC News' Patrick Reevell

Russia's representative to the United Nations on Friday reiterated the Kremlin's claim that Ukrainian forces were responsible for the attack on the Zaporizhzhia nuclear power plant.

The representative said Russian forces came under small arms fire by a "Ukrainian sabotage group" that was stationed in a training complex building on site.

The representative claimed that Russian troops returned fire, but that as they departed, Ukrainians set the building on fire.

The Russian representative claimed Ukrainian "radicals" are under the West's "close guardianship and protection," giving them "carte blanche," and allowing them to act like "ISIS terrorists" by "hiding behind civilians and placing heavy weaponry and multiple rocket launchers in residential areas."

Ukraine, the U.S. and its allies have denied these claims.

The UN relief chief also fact-checked the Russian delegate on Monday, saying Russia's claim about Ukraine placing weapons in civilian areas was false.

- ABC News' Conor Finnegan

The majority of military capability the U.S. promised to send Ukraine, part of a $350 million package, will be delivered within the next week, a senior U.S. defense official told reporters Friday.

In addition to the U.S., 14 countries are also providing military assistance to Ukraine.

The new aid package was expedited so quickly because it has been categorized as “a presidential drawdown,” which bypasses the traditional process of congressional notification, according to the official.

According to another official, this is the largest-ever military support that falls under “a presidential drawdown."

A second official told reporters that weapons were getting into Ukraine through "multiple venues."

Instead of providing new weapons, the U.S. will provide weapons that are in the existing U.S. military arsenal and are eligible to be replaced. The official said the Ukrainians are being provided with weapons they have already received training for in the past.

"I think all of us have been tremendously impressed by how effectively the Ukrainian Armed Forces have been using the equipment that we've provided them," said the official.

Adding, "I think that Kremlin watchers have also been surprised by this, and how they have slowed the Russian advance and performed extremely well on the battlefield."

-ABC News' Luis Martinez

U.S. envoy Linda Thomas-Greenfield addressed the Security Council Friday, warning that, "the world narrowly averted a nuclear catastrophe last night. We all waited to exhale as we watched the horrific situation unfold in real time."

She called Russia's attack on the Zaporizhzhia nuclear power plant "incredibly reckless and dangerous" and said it "threatened the safety of civilians across Russia, Ukraine and Europe."

Thomas-Greenfield urged Russia to withdraw troops from the facility, give operators full access to ensure continued safe operation and assess any damage and to halt any further use of force near Ukraine's nuclear facilities.

She said Russia has killed "thousands of Ukrainians" and "thousands" of Russian soldiers have been killed as well, adding, "President Putin must stop this humanitarian catastrophe by ending this war."

She called on Russia's envoy in the chamber to "say this won't happen again."

International Atomic Energy Agency Director General Rafael Grossi attended the meeting remotely, saying the agency was ready to deploy to Ukraine and establish "basic principles of safety and security starting with the physical integrity" of its nuclear power plants.

Ukraine has requested direct assistance, he said, calling it his agency's "duty" to assist.

The IAEA remains in contact with Ukrainian authorities, including Ukraine's nuclear regulatory agency and the company operating the facility, he said.

-ABC News' Conor Finnegan

While Poland has been welcoming refugees fleeing the destruction in Ukraine, the country will eventually meet its limit on how many people it can take in, Konrad Fijolek, president of Rzeszow, Poland, a city about 60 miles from the Ukrainian border, told ABC News.

Like many cities that border Ukraine, Rzeszow, a town of about 180,000 people, has become a pathway to safety and a lifeline for millions of refugees flooding across the border from Ukraine.

Poland will be able to receive about 1.5 million people, but any more will put the country under strain, Fijolek said.

"If a million or more come, we won't be able to cope," he said.

Some estimates suggest as many as 4 million people could leave Ukraine due to the conflict, but most of the major cities in the country are already full — and officials are attempting to move refugees into smaller cities, a feat that is "not easy," Fijolek said.

So far, all the shelters set up in Poland are temporary, he added.

"We would like to avoid the view of refugee camps here," he said. "We would like people who are escaping from the war to think that what awaits here is proper camp not camps."

In addition, the mental state among the people in Poland is continuing to deteriorate, Fijolek said.

"We as local leaders would like to send the message that if there's any possible action to stop the war [find it] and then try to negotiate, because every day at the border we can see the human tragedy," he said.

-ABC News' Chris Donato and Marcus Moore