Updated at 3:25 a.m. ET Sunday
Late Saturday night, another person threatening the White House was taken into custody, making the third threat in just over a week, and the second in one day.
The Secret Service says a driver was detained after "a suspicious vehicle" approached a White House checkpoint, according to Reuters.
CNN, which first reported the incident, cites two law enforcement sources who said the man claimed to have a bomb in the vehicle. There was no confirmation of an explosive, CNN reports.
Earlier Saturday, U.S. Secret Service agents armed with rifles appeared on the White House north lawn for a few minutes, as the agency dealt with another security scare. Federal officials say the response was prompted by a man who tried to get past a low security fence on Pennsylvania Avenue. The man was arrested without incident. President Trump was in Florida at the time.
The Secret Service issued a brief statement about the incident: "At approximately 1243 pm, an individual jumped over the bike rack on Pennsylvania Ave in an apparent attempt to get to the White House Fence. The individual was immediately apprehended by United States Secret Service Uniformed Division Officers before reaching the White House Fence. As standard operating procedure, Secret Service personnel increased their posture of readiness. Criminal charges are pending."
The response, what one federal official called a "show of force from tactical elements," came just hours after the Secret Service reported that a man who breached the White House perimeter last week spent nearly 17 minutes on the grounds before being captured.
U.S. Rep. Jason Chaffetz (R-UT), chairman of the House Oversight and Government Reform Committee, has sent a letter to the acting director of the Secret Service, demanding a briefing on that incident by March 20 at 5:00 p.m.
The agency's report on last week's fence-jumper came on the same day the agency revealed that a Secret Service employee's agency-issued laptop computer was stolen in New York.
It's unclear what information was on the laptop, but spokeswoman Cathy Milhoan said agency-issued laptops "contain multiple layers of security including full disk encryption and are not permitted to contain classified information."
Some news outlets have reported the laptop contained sensitive information, including floor plans for Trump Tower and information about the investigation into Hillary Clinton's private email server. NPR has not confirmed this.
The Secret Service is asking anyone with information about the theft to contact the New York Police Department and the Secret Service in New York.
The agency says it has taken additional steps to address the security lapse at the White House on March 10, when a suspect, identified as 26-year-old Jonathan Tran, first scaled an outer perimeter fence near the Treasury building, then climbed over an 8-foot vehicle gate and a 3 1/2-foot fence near the East Wing of the White House before being captured. President Trump was in the White House at the time of that security breach.
The statement says the "men and women of the Secret Service are extremely disappointed and angry" about the incident and that steps have been taken to "mitigate lapses in security protocols."
NPR's James Doubek contributed to this report.