Sean Penn Calls the War in Ukraine a 'Brutal Mistake' as He Films His Documentary in the Country

Sean Penn is standing with Ukraine.

The actor, 61, is currently in the country filming a documentary amid Russia's invasion that started earlier this week.

In a statement shared with PEOPLE, Penn calls the war a "brutal mistake" and expresses his thoughts on the horrors that the Ukrainian people are facing.

"[It is] already a brutal mistake of lives taken and hearts broken, and if he doesn't relent, I believe [Russian president] Mr. [Vladimir] Putin will have made a most horrible mistake for all of humankind," he says.

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

Penn is currently on the ground in Ukraine to capture events for an upcoming documentary. He was photographed attending a press briefing on Thursday, Zelenskyy's office told Newsweek in a statement.

"The director specially came to Kyiv to record all the events that are currently happening in Ukraine and to tell the world the truth about Russia's invasion of our country. Sean Penn is among those who support Ukraine in Ukraine today. Our country is grateful to him for such a show of courage and honesty," read the statement, per the outlet.

"Sean Penn is demonstrating bravery that many others have been lacking, in particular some Western politicians," the statement added. "The more people like that — true friends of Ukraine, who support the fight for freedom — the quicker we can stop this heinous invasion by Russia."

The documentary is reportedly a Vice Studios production in association with Vice World News and Endeavor Content, according to Variety.

Russia began its invasion of Ukraine earlier this week, according to the Ukraine government. The attack is still evolving, but explosions and airstrikes have been reported, with threats mounting against the capital, Kyiv, a city of 2.8 million people.

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Putin's aggression towards Ukraine has been widely condemned by the international community, including with economic sanctions and NATO troops massing in the region. Putin, 69, insists Ukraine has historic ties to Russia and he is acting in the interest of so-called "peacekeeping."

"The prayers of the entire world are with the people of Ukraine tonight as they suffer an unprovoked and unjustified attack by Russian military forces," President Joe Biden said as the invasion appeared to begin in force this week.

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Oscar winner Penn is a founder of CORE (Community Organized Relief Effort), which aids in humanitarian efforts. He also starred in a recent discovery+ documentary about how he helped organize relief efforts for Haiti in the wake of a devastating earthquake in 2010.

"I don't fancy myself a good-doer or a bad-doer. I'm just a guy who says, 'Okay, I think I can do this. I think I can do some good here.' And that's it," he said in the doc, Citizen Penn.

The Russian attack on Ukraine is an evolving story, with information changing quickly. Follow PEOPLE's complete coverage of the war here, including stories from citizens on the ground and ways to help.