U.S. Secret Service
© Jonathan Ernst / Reuters
The executive mansion has been locked down for the second time in less than 24 hours. The lockdown is due to an unknown situation, according to reporters in the press briefing room.

The president is believed to be inside the White House.

A Secret Service agent told RT that it "might be an hour" before the lockdown is lifted.

The lockdown was prompted by a package containing papers and a phone that was thrown over the fence, CNN reported. The Secret Service, which protects the president and the White House, is still checking for any possible threats in the area.

A man was taken into custody for throwing the personal belongings over the fence onto the North Lawn, the Secret Service told AP.

The closure on Wednesday morning came just after 11 a.m. local time. On Tuesday, the White House was placed on a brief lockdown after a robbery suspect fleeing the scene jumped over the fence outside the Eisenhower Executive Office Building (EEOB, also known as the Old Executive Office Building) around 4 p.m. The lockdown was lifted about half an hour later.

The man is accused of stealing a woman's purse around 3:45 p.m. on 17th Street NW near Pennsylvania Avenue, then spotted Secret Service Uniformed Division officers patrolling around the EEOB and White House complex, an official familiar with the situation told NBC News. The suspect then jumped the fence to flee the agents, cutting his hand in the process.

He was taken into custody without incident, the Secret Service said, and was treated by EMTs with the DC Fire Department.

The suspect did not appear to know that he hopped the fence into one of the most protected areas of DC, the official told NBC News. The man did not get near the White House grounds, however.

"Initial investigation indicates the individual was fleeing from the scene of a robbery," the Secret Service said in a statement.

The lockdown for the second day in a row provoked some jokes on Twitter.