Former U.S. astronaut Edwin “Buzz” Aldrin has weighed in on the director’s decision to omit a pivotal moment in the upcoming film “First Man”: the planting of the U.S. flag on the lunar surface.

Aldrin appeared to make an indirect swipe at the film through a Sept. 2 post on Twitter that included photos of the flag being planted during the historical 1969 mission. The 88-year-old also wrote a series of hashtags in the post including, in part, #proudtobeanAmerican, #freedom, #honor.

In an earlier post on Aug. 31 Aldrin had flaunted a shirt with a phrase that read “Buzz Aldrin, Future Martian,” and featured an image of an astronaut planting an American flag.

The film delves into the life of Neil Armstrong, played by actor Ryan Gosling, and the Apollo space mission, according to IMDB. Armstrong passed away in 2012 at the age of 82, due to complications following coronary artery bypass surgery. He was the first man to walk on the moon, while Aldrin was the second.

Gosling attempted to hit back at the controversy by defending the move at a press conference during the Venice Film Festival. He said the decision was made deliberately because the moon landing “transcended countries and borders.” The movie, which was directed by Damien Chazelle, will open in theatres on Oct. 12.

“I think this was widely regarded in the end as a human achievement [and] that’s how we chose to view it,” Gosling told reporters. “I also think Neil was extremely humble, as were many of these astronauts, and time and time again, he deferred the focus from himself to the 400,000 people who made the mission possible.”

He added, “He was reminding everyone that he was just the tip of the iceberg—and that’s not just to be humble, that’s also true. So I don’t think that Neil viewed himself as an American hero.”

But Gosling’s response just sparked more criticism. U.S. Sen. Marco Rubio (R-Fla.) argued that the film is based on a historically American mission.

“This is total lunacy. And a disservice at a time when our people need reminders of what we can achieve when we work together,” Rubio wrote in an Aug. 31 Twitter post. “The American people paid for that mission, on rockets built by Americans, with American technology & carrying American astronauts. It wasn’t a UN mission.”

American actor James Woods also criticized the film for not presenting the whole truth.

“But why not just present the facts as they were?” he wrote in an Aug. 31 Twitter post. “I think Ryan Gosling is a wonderful actor, but omitting the seminal moment in the midst of mankind’s greatest achievement seems a purposeful denigration of the 400,000 Americans who accomplished it.”

The upcoming movie comes on the heels of President Donald Trump’s proposal of a sixth branch of the U.S. Armed Forces, dubbed the “Space Force.” Trump directed the Department of Defense to create the new military branch through an executive order on June 18.

Aldrin showed his support for Trump’s move in August, with a close reference to the famous quote by Armstrong, “That’s one small step for man, one giant leap for mankind.”

Aldrin praised Trump at the time by writing on Twitter, “One giant leap in the right direction. #SpaceForce,” while replying to Vice President Mike Pence, who had recently unveiled the steps in creating the branch.