More than 400 law enforcement personnel have been deployed as police search for the suspect in a shooting at Brown University in Rhode Island in which two students were killed and nine wounded, US officials said.

The Ivy League university in Providence remained in lockdown early on Sunday, several hours after a suspect with a firearm entered a building where students were taking exams on Saturday. Streets around the campus were packed with emergency vehicles hours after the shooting, and security was heightened around the city as law enforcement agencies continued their manhunt.

The suspect remained at large, officials said, as police worked with agents from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives to search streets and buildings around the campus to find the individual.

Saturday’s shooting is the second major incident of gun violence on a university campus this week.

Providence deputy police chief Timothy O’Hara said the suspect had not been identified.

Officials said they would release a video of the suspect, a male possibly in his 30s and dressed in black, who O’Hara said may have been wearing a mask. He said officials had retrieved shell casings from the scene of the shooting, but that police were not prepared to release more details of the attack.

Providence Mayor Brett Smiley has confirmed that two students were killed and nine people were injured in the attack.

At a news conference, Smiley said university leaders became aware of the shooting at about 4:05pm local time (21:05 GMT), when emergency responders received a 911 call.

Smiley declined to identify the shooting victims, citing the ongoing investigation. However, he sought to reassure the community, despite a shelter-in-place order for the Brown campus and the surrounding neighbourhood.

“We have no reason to believe there are any additional threats at this time,” he said.

The university’s president, Christina Paxton, explained she had been on a flight to Washington, DC, when she learned of the shooting. She immediately returned to Providence to attend a night-time news conference.

“This is a day that we hoped never would come to our community. It is deeply devastating for all of us,” Paxton said in a written statement.

At the news conference, Paxton said she was told the victims were students.

Suspect remains at large

At approximately 4:22pm local time (21:22 GMT), the university issued its first emergency update, warning that there was an armed man near the Barus and Holley engineering and physics building.

“Lock doors, silence phones and stay hidden until further notice,” the university said in its update.

“Remember: RUN, if you are in the affected location, evacuate safely if you can; HIDE, if evacuation is not possible, take cover; FIGHT, as a last resort, take action to protect yourself.”

Upon arriving at the scene, law enforcement swept the building, according to Providence police’s O’Hara.

“They did a systematic search of the building. However, no suspect was located at that time,” O’Hara said.

The university had to withdraw an early announcement that a suspect had been apprehended, writing, “Police do not have a suspect in custody and continue to search for suspect(s).”

US President Donald Trump published a similar retraction on his online platform, Truth Social, after erroneously posting at about 5:44pm (22:44 GMT) that a suspect had been detained.

Mayor Smiley said there were 400 law enforcement officers in the area to search for the suspect.

He also encouraged witnesses to come forward with any information about the shooting.

The seventh-oldest university in the US, Brown is considered part of the prestigious Ivy League, a cluster of private research colleges in the northeast. Its student body numbers 11,005, according to its website.

On December 9, Kentucky State University in the southern city of Frankfort also experienced gunfire on campus, killing one student and leaving a second critically injured.

The suspect in that case was identified as Jacob Lee Bard, the parent of a student at the school.