The alleged gunman in Saturday’s mass shooting at a Pittsburgh synagogue spewed anti-Semitic posts on a social media platform where he claimed that Jews were "the enemy of white people," according to a report.

Two hours before Robert Bowers, 46, allegedly burst into the Tree of Life Synagogue and opened fire during a Shabbat service, he posted on the chat site Gab.com about the Hebrew Immigrant Aid Society, the New York Times reported.

“HIAS likes to bring invaders in that kill our people. I can’t sit by and watch my people get slaughtered. Screw your optics, I’m going in,” a message attributed to Bowers said.

HIAS, a Maryland-based nonprofit, helps refugees around the world and is guided by Jewish values, according to the organization.

In total, Bowers allegedly killed 11 people and wounded at least six, including four police officers. He was also wounded and taken to a hospital with non-life-threatening injuries.

A criminal complaint said the 11 dead were eight men and three women, the Pittsburgh Post-Gazette reported. Authorities did not immediately identify them.

Mark Hetfield, president and CEO of HIAS, told the Associated Press he wasn’t aware of Bowers "until this morning," meaning after the shooting.

A U.S. attorney in Pennsylvania filed 29 federal charges against Bowers Saturday night, the Post-Gazette reported. The suspect also faces local charges, the report said.

The federal charges include 11 counts of obstruction of exercise of religious beliefs resulting in death; 11 counts of use of a firearm to commit murder during a crime of violence; four counts of obstruction of exercise of religious beliefs resulting in bodily injury to a public safety officer and three counts of use and discharge of a firearm during a crime of violence.

PITTSBURGH SYNAGOGUE SHOOTING LEAVES 11 DEAD AND 6 WOUNDED; SUSPECT HIT WITH MULTIPLE CHARGES

“The actions of Robert Bowers represent the worst of humanity,” said Scott W. Brady, the U.S. attorney for the Western District of Pennsylvania. “Please know that justice in this case will be swift and it will be severe.”

Gab.com promotes itself as a free-speech alternative to sites like Twitter, which some critics say monitors content too rigidly. Just recently, President Trump complained that Twitter had purged some of his followers.

Since the Bowers account launched on Gab in January, there have been frequent posts on the account about Jews, including conspiracy theories, according to reports by the New York Times and Associated Press.

One post read: “Open your eyes! It’s the filthy EVIL jews Bringing the Filthy EVIL Muslims into the Country!!”

Another featured a photo of a Nazi concentration camp used to cremate Jews. A caption read “Make Ovens 1488F Again.” The first two words refer to the white supremacist “14 Words” slogan and “88” stands for “Heil Hitler” because “H” is the eighth letter of the alphabet.

Other posts featured conspiracy theories about the Holocaust, in which six million Jews perished during World War II.

Other Bowers posts criticized President Trump, according to the reports. In one post, he called the president a “globalist, not a nationalist. There is no #MAGA as long as there is a [slur for Jews] infestation.”

A month ago, he posted photos of three handguns he called his “glock family,” Reuters reported.

Gab.com said in a statement that it suspended Bowers' account after his name was mentioned on police radio chatter about the Pittsburgh shooting. It then backed up the content on the account and alerted the FBI, the company said.

“Gab unequivocally disavows and condemns all acts of terrorism and violence,” a statement read.

Gab's founder and CEO posted that PayPal has banned the site from using its online payment service.

"The company is diligent in performing reviews and taking account actions. When a site is explicitly allowing the perpetuation of hate, violence or discriminatory intolerance, we take immediate and decisive action," PayPal spokesman Justin Higgs said.

Police said Bowers had 21 guns registered in his name and was not known to law enforcement before the shooting. He is a registered voter with “no affiliation” in Allegheny County, Pa.

“For the record, I did not vote for him nor have I owned, worn or even touched a MAGA hat,” he once posted on social media, referring to President Trump.

The shooting follows a pattern of massacres in places of worship and comes days after mail bombs were sent to prominent Democrats. Florida resident Cesar Sayoc Jr. has been charged in connection with the explosive devices.

After the shooting, dozens of law enforcement officers descended on Bowers' neighborhood, which is about a 25-minute drive from the synagogue.

One man who said he lived in the area for more than 15 years shook his head, noting that many immigrant families had recently moved in.

Another woman told the Times she had struggled to understand violent hate.

“I can’t believe it has spread out this far,” she said.