One of the assailants held the door for the other two after nearly 100 worshippers had gathered at the Islamic Congregation of North Jersey on Preakness Avenue -- one of five services held each day -- shortly after 8:30 p.m. Monday.
Two people were hit, but neither was seriously injured, authorities said Thursday.
Mosque officials said they had no choice but to begin locking the doors after this week's bias attack, which followed another involving an intruder late last year.
The mosque, which opened seven years ago and is also known as Masjid Abu Bakr, has a mostly Bengali congregation.
City police and members of Passaic County Sheriff Richard H. Berdnik's office are also keeping an eye on the house of worship.
Berdnik and Passaic County Prosecutor Camelia M. Valdes asked that anyone with information that can help identify the assailants call specially-designated tip lines at the prosecutor's office (1-877-370-PCPO or tips@passaiccountynj.org) or the sheriff's office (973-881-4200).
A Paterson man was charged with bias assault after he pushed and struck an assistant Imam at the mosque in late December while complaining about the amplified daily call to prayer, authorities said.
Known as the adhan (literally: "to listen"), the call reminds Muslims to attend mandatory prayer and leave immediate concerns behind.
SEE: Man Angered By Call To Prayer Charged With Assault At NJ Mosque, Sheriff Says
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