This is a breaking news story. Check back for updates.
UPDATE 3:03 p.m. EDT: The lockdown has ended, according to the 436th Airlift Wing's Twitter account, The airlift wing operates out of Dover AFB; the account gave no further information on the situation:
As of 2:40 p.m. the base is no longer on lockdown. We appreciate your patience and apologies for the inconvenience.
— 436th Airlift Wing (@436AirliftWing) May 8, 2014
UPDATE 1:41 p.m. EDT: There are no reports of injuries in connection with the reports of a suspicious person on Dover Air Force Base, CBS Philadelphia reported. The station said Delaware State Police are aware of the reports but so far have not been involved in the investigation.
UPDATE 1:09 p.m. EDT: There are conflicting reports as to whether there is an active shooter on the base. A source told IBTimes that they heard base personnel were responding to an active shooter in Building 706, The Wilmington News Journal, citing a school director whose students were touring a museum on the base, also reported the possibility of an active shooter, but a base spokesman would not confirm the reports..
"At this time we have no information that would lead us to believe that there is an active shooter on the base," Airman First Class William R. Johnson told the newspaper.
UPDATE 12:29 p.m. EDT: There were no reports of shots fired at Dover Air Force Base, CBS News tweeted, citing a federal law enforcement official.
UPDATE 12:09 p.m. EDT: Dover Air Force Base confirmed the lockdown and said the suspicious person was reportedly near Building 706.
"The safety of our people is our top priority," said Col. Randy Huiss, 436th Airlift Wing vice wing commander. "We take this report very seriously and are taking the necessary precautions to investigate this matter."
A person on the base who spoke to IBTimes and requested anonymity described the scene. The source said they were in another building and didn't receive word of a resolution as of 12 p.m. EDT.
"They came in and told us we can't go outside. The gates are closed," the source said. "We're getting information but nothing's really coming across. It's kind of a distraction at this point. It seems to be an isolated incident on another part of the base."
"People are checking their phones to see if it's a drill," the source added. "It doesn't look like it's a drill."
Dover Air Force Base in Delaware was put under lockdown Thursday morning following reports of a suspicious person on the base. The base was put on alert around 11 a.m. EDT Monday, a base spokesman told NBC Philadelphia.