(NBC Connecticut) -- Classes at Central Connecticut State University, a public university in New Britain, Connecticut, are canceled for the rest of the day and one person is in custody after a massive police search for a man who was reportedly carrying a gun.

A source with the state said state police have contained a suspect within James Hall on the CCSU campus.

Now, a police source tells NBC Connecticut that everything is secure and they are speaking to several people.

The Twitter account for CCSU's office of marketing and communications reports that one person is in custody and the shelter in place order remains in place until police give an "all clear."

A news conference will be held at 4 p.m.

CCSU issued a campus emergency alert this afternoon after a potentially armed man was seen entering one of the halls at CCSU, according to police sources.

NBC Connecticut crews saw police escorting someone out of James Hall in handcuffs. It was not immediately clear if this is in connection with the massive police presence on campus for much of the afternoon.

A student also reported seeing two people escorted, but officials have not confirmed that.

New Britain Mayor Tim O'Brien has been on the campus and said there are no injuries to report.

When school officials issued the alert, they asked everyone on campus to seek shelter, stay indoors, lock doors, close windows, keep quiet and put cell phones on silent or vibrate as police search for a suspicious person.

They said there had not been a shooting and there was no active shooter.

Soon after the alert was issued, sate police said they have a "number of troopers" at the scene at the request of CCSU police. Tactical and SWAT teams have also responded.

Witnesses said police were running with long guns, telling students to take cover.

Two students reported seeing a masked man in camouflage walking on campus with a sword and carrying a backpack away from his body. Whether this is connected to the alert is not yet known.

Residents of James Hall report hearing an alarm go off, then police knocking on doors and telling students who live on the first floor to evacuate to nearby Carroll Hall, which is across the quad.

Officials from the governor's office said earlier today that Gov. Dannel Malloy has been briefed.

The university has more than 10,000 students attending the school.

Two New Britain schools are on lockdown, according to Supt. Kelt Cooper.

Holmes Elementary, at 2150 Stanley St., is on external lockdown out of an abundance of caution, Cooper said. Children are not going outside, but they can move around freely inside.

House of Arts Letters and Sciences Academy, or HALS, located at 30 Pendleton Road, is very close to campus and is on full lockdown.