Jackie Rahm Little, the man accused of setting fires at two Minneapolis mosques, was charged Thursday with a federal hate crime for intentionally damaging religious property.

The hate crime charge is on top of an existing arson charge. At a news conference, U.S. Attorney Andrew Luger said prosecutors are considering additional civil rights charges.

"The investigation of Little is continuing, as we seek to learn more about his motivation and actions," Luger said.

The federal charges accuse Little, 36, of setting separate fires on April 23 and 24 at the Masjid Omar Islamic Center and Masjid Al Rahma mosque, acts that alarmed the Twin Cities Muslim community and raised concerns about safety at mosques and other gathering places.

The complaint alleges Little set both fires, but the arson charge is linked only to the second fire at Masjid Al Rahma, on Bloomington Avenue.

On the night of April 24, the charges say, Little went to the Masjid Al Rahma mosque and started a fire on the third floor when worshipers and 40 day care children were in the building. Firefighters extinguished the blaze before it spread to the lower levels, but community leaders said damage estimates are around $50,000. Little was arrested five days later in Mankato.

Little also faces a state arson charge for that fire. His attorney did not return requests for comment Thursday. Little made his second federal court appearance Thursday, pleading not guilty.

Luger declined to comment on Little's motives but said investigators are looking into his past for the potential added charges.

"We all want to assure the Muslim community, and members of all faith communities, that we respond to attacks on houses of worship at the highest levels and with utmost urgency," Luger said.

The complaint and Little's criminal history show a pattern of targeting Muslims, including U.S. Rep. Ilhan Omar.

Little's mother told investigators he had also "extensively harassed" a Muslim woman when he was in transitional housing.

Little has been committed to hospitals three times in recent years, and in those cases doctors have said he is likely to harm other patients or staff due to his bipolar disorder.

Liliana Zaragoza, a clinical law professor and director of the University of Minnesota's Racial Justice Law Clinic, said she thinks the string of cases where Little is accused of targeting Muslims is strong evidence for a hate crime-based prosecution.

"It's evidence that is not always available in these kinds of cases," Zaragoza said. She added that it "shows a very specific aim that this person appears to have."

Minneapolis Police Chief Brian O'Hara also attended the news conference at the federal courthouse in Minneapolis, along with Hennepin County Attorney Mary Moriarty, and other federal representatives.

O'Hara said the arrest of Little in Mankato came after a dispatcher for the Blue Earth County Sheriff's Office was made aware that Little was in the area.

"There was a lot of intense work going on every single day since the first fire," O'Hara said. "We were really close for a couple of days."

Jaylani Hussein, CAIR-MN executive director, said the arrest and charges have been a "huge relief" to the state's Muslim community. In the days after the fire, Hussein said there was some heightened fear, with mosque leaders sending security images or videos of people they suspected of trying to break in.

"I was getting messages daily from mosques, leaders who were taking snapshots of people suspicious at their mosque, some guy jiggling doors, coming around it multiple times."