(STMW) — Northern Northern Illinois University branch campuses were evacuated Thursday after what appeared to be a hoax bomb threat, according to a statement on NIU’s website.

All classes and activities were canceled for the night at the DeKalb, Hoffman Estates, Naperville and Rockford campuses, said Joe King, an NIU spokesman.

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By 11 p.m., NIU said all residence halls on the main campus had been cleared and police were working through the night to check other campus buildings. Friday classes were expected to be held as usual.

Officials said the Naperville, Hoffman Estates and Rockford campuses also were clear by 10 p.m., but the campuses were closed for the night. The Holmes student center was reopened and students were allowed to go back inside.

Campus police received a phone call of a bomb threat at 6 p.m., according to the statement.

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About 8:30 p.m., officials said it appeared that the threat was a hoax “and one of a series of bogus bomb threats called into a number of colleges and universities across the region,” according to the statement.

Earlier in the evening, DePaul University’s O’Hare branch also received a bomb threat, according to a spokeswoman.

Fifty students were evacuated as a precaution, but classes weren’t canceled. As of 6:45 p.m., the campus was given the “all clear,” the spokeswoman said.

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(Source: Sun-Times Media Wire © Chicago Sun-Times 2015. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)