Actor Sean Penn is continuing to voice his support for Ukraine amid Russia’s unprovoked invasion of the country.

The 61-year-old “Dead Man Walking” star has been working on a documentary about escalating tensions in the country since last year, and flew to Ukraine in February to get a firsthand look at the war.

After spending some time on the ground in Kyiv, the actor told Hollywood Authentic magazine that he recently thought about taking up arms against Russia.

“If you’ve been in Ukraine [fighting] has to cross your mind,” Penn said in the interview published Saturday.

“And you kind of think what century is this? Because I was at the gas station in Brentwood the other day and I’m now thinking about taking up arms against Russia? What the f— is going on?”

Penn continued: “The only possible reason for me staying in Ukraine longer last time would’ve been for me to be holding a rifle, probably without body armor, because as a foreigner, you would want to give that body armor to one of the civilian fighters who doesn’t have it or to a fighter with more skills than I have, or to a younger man or woman who could fight for longer or whatever.”

The Ukrainian embassy released a statement on Penn’s efforts to film the documentary following the actor’s visit to Kyiv.

“Sean Penn demonstrates the courage that many others, especially Western politicians lack. The more such people in our country now, true friends of Ukraine, who support the struggle for freedom, the sooner it will be possible to stop Russia’s treacherous attack,” the Ukrainian embassy told Newsweek in a translated statement.

In his Hollywood Authentic interview, Penn also opened up about meeting Ukrainian President Volodymyr Zelensky “the day before the invasion” and being with him “during the invasion, on day one.”

Seeing Zelensky on that day, he said, “it struck me that I was now looking at a guy who knew that he had to rise to the ultimate level of human courage and leadership. I think he found out that he was born to do that.”

Russia’s attack on Ukraine continues after Russian President Vladimir Putin ordered a large-scale invasion on Feb. 24 using land, air, and naval forces.