Russian forces severed the electricity to the Chernobyl nuclear power plant but there is "no immediate risk" of a radiation leak, International Atomic Energy Agency (IAEA) Director-General Rafael Mariano Grossi told ABC News in an interview Wednesday at the agency’s headquarters in Vienna.

There is active fuel at the site of the original reactors that melted down in 1986 but, for the time being, at least, there is enough capacity to cool spent nuclear fuel.

"There is no immediate risk in the dimensions that were imagined and there is work in progress to restore the electrical capacity," Mariano Grossi said. Still, he conceded, "It's a situation that is very fragile."

The lack of reliable electricity also impedes monitoring abilities, leaving the IAEA -- the nuclear watchdog of the United Nations -- occasionally blind to any spontaneous increase in radiation.

"We do have communications and then we lose. Then we recover it. It's not good in terms of following the safety, the security," Mariano Grossi said. "I'm concerned. I’m worried."

There are no IAEA inspectors on the ground while the fighting rages. The director-general said he would not send them in unless he can go first.

"I will not put my staff in harm’s way before me going first," Mariano Grossi said.

Russia is in control of Chernobyl and a second nuclear power station in Zaporizhia. For a time, neither plant had a way to exchange workers or upgrade staffing.

In Zaporizhia, Mariano Grossi said, a shift change is now happening. In Chernobyl, workers are not allowed off-site.

"We all need a break and especially people who are manning extremely sophisticated equipment. The stress is very high," he said.

Mariano Grossi is traveling Thursday to Turkey, where the Russian and Ukrainian foreign ministers will meet face-to-face for the first time since the two-week-old invasion began. He said he will ask each side to commit to "fundamentals," including respecting the physical security of each of Ukraine’s four nuclear power stations, plus Chernobyl.

"We haven't seen something as critical and worrying as a fire breaking out in a building adjacent to a nuclear reactor," Mariano Grossi said. "What really worries me is that unlike Fukushima (in Japan), where you had mother nature to blame, now it would be us."

-ABC News' Aaron Katersky and Robert Zepeda

House Minority Leader Kevin McCarthy broke with former President Donald Trump on Wednesday when he was asked whether he supported Trump's comments praising Putin as a "genius."

“I do not think anything is savvy or genius about Putin," McCarthy, R-Calif., said during a news conference. "I think Putin is evil, he is a dictator and I think he is murdering people right now."

On Feb. 23, a day before the start of the Russian invasion of Ukraine, Trump praised Putin and slammed his successor President Joe Biden in an appearance on a conservative talk radio program.

"This is genius. Putin declares a big portion of the Ukraine ... Putin declares it as independent. Oh, that's wonderful," Trump said of the Russian president's decision to recognize the two provinces of the Donbas Region of eastern Ukraine as independent republics and claimed rebels there asked him to send troops into Ukraine to protect them from Ukrainian military attacks.

Secretary of State Antony Blinken called on the Kremlin to immediately allow Ukrainian civilians to safely depart the cities and towns of Ukraine that are besieged by Russian forces.

Blinken accused Russia of destroying critical civilian infrastructure and blocking people's safe exodus, describing the Kremlin's proposed corridors to Russia "absurd" and "offensive” in a press conference Wednesday.

"Russia's relentless bombardment, including of civilians trying to flee, prevents people from safely escaping the hellish conditions that they've created,” Blinken 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

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