Joint Base Andrews, the Maryland facility used by planes carrying the president and vice president, was placed on lockdown Sunday night when a vehicle carrying two people drove through a security checkpoint, resulting in the apprehension of one suspect and an hourslong manhunt for the other.

The incident unfolded just moments after Vice President Kamala Harris, her husband and four Cabinet secretaries landed at the military base following a trip to Alabama to commemorate the 57th anniversary of the civil rights march on the Edmund Pettus Bridge in Selma. 

According to the press pool reporter covering Harris on Sunday, the vice president and second gentleman Doug Emhoff apparently left Joint Base Andrews in the Marine Two helicopter just before the security breach. 

It’s unclear when Housing and Urban Development Secretary Marcia Fudge, Education Secretary Miguel Cardona, Transportation Secretary Pete Buttigieg and Environmental Protection Agency Administration Michael Regan left the base, but a White House official said they all had safely departed Sunday night. 

A 17-year-old male in possession of a firearm was taken into custody, Joint Base Andrews said on social media Monday morning. The other person remains at large, but there is evidence the person left the base, it said.

According to the military base, the vehicle blew past the security checkpoint and ignored orders at the main gate around 9 p.m. Eastern. Security personnel immediately deployed barriers and stopped the vehicle. Two individuals fled the vehicle on foot — one being captured, the other getting away, according to officials.

No shots were ever fired, officials said. Its unknown if the suspect who is at large had a weapon.

Security personnel searched the grounds into the morning before concluding the intruder who was unaccounted for had left the base. The main gate reopened around 3 a.m., six hours after it had closed.

Units from Prince George’s County Police, Maryland State Police, the Metropolitan Police Department and the Office of Special Investigation also responded to the incident. 

"I am incredibly proud of the quick actions of our Defenders to immediately deploy the barriers to stop last night's stolen vehicle and then apprehend one of the individuals that had a weapon,” Col. Tyler Schaff, Joint Base Andrews installation commander, said in a statement. “The Defenders handled the intense situation with discipline and calm professionalism. We are also thankful for our partnerships with local authorities, who responded rapidly on base to assist the 316th Security Forces Group throughout the night.”

The incident remains under investigation.