Authorities have arrested three additional suspects in connection to the Boston Marathon bombings, the Boston Police Department confirmed to Yahoo News Tuesday.

A spokeswoman at the department directed all questions related to the suspects to the FBI, which has yet to disclose their identities. Local news station WBZ reports that they will be brought to a federal courthouse in Boston this afternoon to face charges of aiding the suspect after the fact. A spokeswoman for the U.S. attorney in Boston declined to comment.

NBC’s Pete Williams reported that the suspects are friends of Dzhokhar Tsarnaev’s from the University of Massachusetts at Dartmouth. The three have been under FBI surveillance for 10 daysand are suspected of aiding Tsarnaev after he allegedly committed his crimes. Two have been in custody on immigration charges related to their student visas, while a third, a U.S. citizen, was arrested today.

The Associated Press identified two of the suspects: Azamat Tazhayakov and Dias Kadyrbayev, both Kazakh nationals who came to the U.S. on student visas. They were detained on civil immigration violations on April 20 and have been in federal custody since then. The two appeared in immigration court Wednesday morning.

Boston attorney Linda Cristello, who represented the two, confirmed in an email to Yahoo News that her clients now face additional federal charges and will appear in court Wednesday afternoon. She referred further questions to a new team of lawyers representing the suspects in this case. One of the attorneys, Harlan Protass, a criminal defense attorney based in New York, declined to comment on the charges until after the court hearing.

Tsarnaev, a 19-year-old college student, is charged with killing three and injuring more than 200 in the two bombs last month. He is in custody at a federal prison medical facility at Fort Devens, 40 miles outside of Boston, where he is being treated for injuries incurred in a shootout with police before his arrest. His older brother and suspected co-bomber, Tamerlan Tsarnaev, was killed while fleeing arrest.

In a statement, the Police Department said there was no threat to public safety at this time.