Investigators said a man was accused of throwing a Molotov cocktail at protesters to attend a parade of hostages in Israel on Sunday, planning a year-long attack.

Mohammed Sabry Soliman, 45, was charged with federal hate crimes and attempted murder, assault and use of explosive devices and briefly appeared in court on Monday.

Egyptian nationals targeted a group of pro-Israeli protesters at an outdoor shopping mall in Boulder and yelled "Free Palestine" as he threw a burning device, officials said, injured eight of them.

At least 16 unlit Molotov cocktails were found nearby. Investigators said he found the team online and targeted it.

This is the latest attack on members of the American Jewish community.

Weekly demonstrations are organized through their lives, which raises awareness of Israeli hostages still in Gaza.

Officials said Mr Soriman threw two combustion devices into a party at the Pearl Street Mall, with eight victims suffering burns.

Twelve people, including four men and four women between the ages of 52 and 88, were taken to the hospital with injuries ranging from minor to serious injuries.

Officials have previously said there were eight victims, but four more were slightly injured on Monday.

The victim's eldest son is a Holocaust survivor, Rabbi Israel Wilhelm, director of CHABAD at the University of Colorado Boulder University, told BBC's U.S. partner CBS News.

The attack occurred at the beginning of Shavuot's Jewish holiday.

The suspect appeared in court less than five minutes through a video feed of the Boulder County Jail on Monday, standing and wearing an orange jumpsuit.

He answered "yes" to some of the judge's procedural questions, but otherwise he did not speak. The court plans to formally file the charges this Thursday.

Officials said Monday they think he was acting alone.

In an interview after his arrest, Mr Soriman told police that he had planned the attack for a year after his daughter's high school graduation, according to the FBI's arrest warrant.

Court documents said he told police he wanted to "kill all Zionists" and would conduct another attack.

In addition to Molotov's cocktails, backpack herbicides containing octane gasoline were found nearby.

According to police, Mr Soriman dressed as a gardener and had an orange vest to get as close to a group of people as possible.

Mr Soliman said he had been watching YouTube videos on how to make a Molotov cocktail, the affidavit said.

Investigators said he told them he learned to shoot guns in hopes of obtaining a hidden Kari license, but ended up using a Molotov cocktail because his immigration status prevented him from obtaining the gun.

Mr Soriman drove to Boulder from his home in Colorado Springs and arrived at the group five minutes before the meeting, according to court documents. He allegedly said he bought gasoline on the way to the offense.

Throughout the interview, Soliman said he hated Zionists and targeted them because they needed to stop taking over “our land,” according to the FBI, which he said was a term for Palestinian territory.

Mr Soriman allegedly told officials that he hid his iPhone in a desktop drawer and left messages to his family, his wife and five children. His wife later brought the iPhone to officials, according to court documents.

Law enforcement officers said Monday there was no previous indication that the defendant was a threat.

“We are totally going to hold Mr. Soliman responsible for his actions and these allegations are the first step,” a U.S. attorney for J Bishop Grewell Grewell, Colorado, said in a press conference Monday.

Mr. Soriman moved to Colorado Springs three years ago and had lived in Kuwait for 17 years.

Several sources told CBS News that in 2022, Mr. Soriman arrived in California with a non-immigrant visa expired in February 2023.

Homeland Security officials said he applied for asylum one month after arrival but did not provide detailed information on the outcome of the immigration case or whether it was resolved.

President Donald Trump's deputy chief of policy Stephen Miller said on X that Mr. Soriman had obtained a work permit after visiting his visa.

"In view of yesterday's terrorist attacks, all terrorists, their families and terrorist sympathizers should know that under the Trump administration, we will find you, revoke your visa and deport you," said U.S. Secretary of State Marco Rubio on X.

A company spokesperson told CBS that Mr Soliman has been working as a delivery driver for Uber since 2023.

According to the company, when he started working for them, he met all Uber requirements, including through criminals and driving history background checks, providing photo IDs and holding a valid Social Security number.

Trump said in a social media post that as attacks by Mr. Soliman would be intolerable.

"This is another example of what we have to ensure borders are safe and expel illegal anti-American activists from our homeland," he said.

The Jewish community in the United States faces a series of attacks by invoking attackers in the Israeli-Gaza War.

Last month, two Israeli embassy aides were shot and killed outside the Jewish Museum in the capital of Washington. Witnesses said the attackers shouted "Free Palestine".

In April, a man caught fire on the residence of Pennsylvania Governor Josh Shapiro, who is Jewish. The suspect said the arson was retaliation against Israel's attack on the Palestinians.