Sean Penn spoke with Ukrainian President Volodymyr Zelenskyy's Chief of Staff Andriy Yermak on Wednesday.

Following the conversation, the actor, who has been in Ukraine since the war with Russia began, took to Twitter to weigh in on the country's need for jets.

"I JUST got off a call with President Zelensky’s Chief of staff, Andriy Yermak," he wrote. "Somewhere in the bureaucratic chain between our White House & the Polish Gov., the desperately NEEDED jets are not yet delivered to Ukraine. Public outcry may find the bottleneck."

Poland offered to give its entire fleet of MiG-29 fighter jets to the U.S. in exchange for a chance to buy American F-16s as part of a deal to bolster the Ukrainian air force while upgrading the Poles’ with NATO aircraft.

SEAN PENN ARRIVES IN UKRAINE TO FILM DOCUMENTARY ON RUSSIAN INVASION

Ukrainian defense officials for days have been asking for help with supplies ranging from helmets to ammunition and fighter jets, a request that Poland appeared ready to fulfill almost two weeks into Russia’s invasion of its smaller neighbor.

Earlier Tuesday, a bipartisan group of U.S. lawmakers sent a letter to President Biden urging him to support a deal with Poland.

But Pentagon press secretary John Kirby distanced the U.S. from the proposal later in the day, saying that while the decision to hand over jets to Ukraine is in the hands of the Polish government, American involvement "raises serious concerns for the entire NATO alliance."

He said the U.S. would continue talks with Poland and the rest of NATO regarding the issue.

For Penn's part, the actor also shared an article Wednesday published by The Telegraph headlined, "It is the world's duty to do all we can to stop Vladimir Putin."

Sean Penn

Sean Penn called on the United States and Poland to supply Ukraine with much-needed jets amid the ongoing war with Russia. (Presley Ann)

SEAN PENN ‘WALKED MILES’ TO POLAND BORDER FOR DOCUMENTARY ON UKRAINE-RUSSIA CRISIS

Penn "walked miles" to the border of Poland Feb. 28 from Ukraine, where he has been filming a documentary about Russia's invasion.

The actor took to Twitter to share an update just days after it was revealed he was in Kyiv to film a documentary about the escalating conflict.

"Myself & two colleagues walked miles to the Polish border after abandoning our car on the side of the road," Penn revealed in a tweet.

"Almost all the cars in this photo carry women & children only, most without any sign of luggage, and a car their only possession of value," he added.

Sean Penn

Penn attends a press briefing at the Presidential Office in Kyiv, Ukraine, Feb. 24, 2022. (Ukrainian Presidential Press Service/Handout via REUTERS )

CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTER

Penn previously condemned Russian President Vladimir Putin and applauded Ukrainian President Volodymyr Zelenskyy for his response to the conflict.

"Already a brutal mistake of lives taken and hearts broken, and if he doesn’t relent, I believe Mr. Putin will have made a most horrible mistake for all of humankind," Penn said in the statement, which he later shared to Twitter. 

The "Fast Times at Ridgemont High" actor went on to praise the people of Ukraine and their leader for their bravery.

CLICK HERE TO GET THE FOX NEWS APP

Actor Sean Penn

Penn revealed the needed jets had not arrived in Ukraine after getting off a call with Ukrainian President Volodymyr Zelenskyy's Chief of Staff Andriy Yermak. (REUTERS/Andrew Kelly - RTSNMNG)

"President Zelenskyy and the Ukrainian people have risen as historic symbols of courage and principle," he wrote. "Ukraine is the tip of the spear for the democratic embrace of dreams. If we allow it to fight alone, our soul as America is lost."

Russian President Vladimir Putin launched a full-scale attack on Ukraine Feb. 24.

On Wednesday, a Russian airstrike devastated a maternity hospital in the besieged port city of Mariupol amid growing warnings from the West that Moscow’s invasion is about to take a more brutal and indiscriminate turn. Ukrainian officials said at least 17 people were wounded in the attack.

Fox News' Melissa Roberto and Michael Ruiz as well as The Associated Press contributed to this report.