Armed man outside White House refuses to stop, shot at

A man, who brandished a gun and refused orders by US Secret Service agents outside the White House to stop, was shot at and critically injured even as the official residence of the American President was put on lockdown for over an hour.

The incident took place at around 3.06 PM (local time) yesterday when an "adult male subject, carrying a firearm, approached an outer perimeter checkpoint accessible to the general public" on E Street near the White House, the Secret Service said.

The Secret Service agents on duty gave numerous verbal commands for the accused to stop and drop the firearm.

"When he failed to comply with the verbal commands, he was shot once by a Secret Service agent and taken into custody," said David A Iacovetti, Deputy Assistant Director Office of Government and Public Affairs, United States Secret Service.

"The Secret Service recovered a firearm at the scene," he said.

The man has been admitted to a nearby hospital with critical injuries, officials said.

As a precautionary measure following the incident, the White House was immediately put under lockdown, with doors locked and agents in full tactical gear and armed with automatic and heavy-caliber weapons deployed around the complex and Lafayette Square to the north.

Snipers took to the White House roof with guns drawn as people were cleared off the streets. Some people were heard screaming on Pennsylvania Avenue.

President Barack Obama was not present on the premises at the time of the incident as he had gone to play golf at Andrews Airforce Base.

Vice President Joe Biden was in the complex and the Secret Service agents rushed to him for additional security.

During a search of the man's vehicle parked near 17th Street and Constitution Avenue, federal agents found ammunition for a .22 caliber weapon.

Based on preliminary investigation, the Federal Bureau of Investigation and other law enforcement agencies said the shooting incident has no known nexus to terrorism.

"At this time, based on a preliminary investigation, there is no known nexus to terrorism," said a joint statement issued by multiple agencies involved in the investigation including the Metropolitan Police Department, United States Secret Service, United States Park Police, and Federal Bureau of Investigation.

"However, an investigation continues into the motives behind his actions. The investigation is ongoing, and will continue to follow all logical leads," said the statement issued late in the night.

No law enforcement personnel and bystanders were injured during the incident.The White House has seen a number of security incidents in recent years, prompting changes at the executive complex.

Just last month, a person was detained by secret service agents for allegedly throwing a backpack over the White House fence and then climbed over the barrier.

In other recent security breaches, Iraq War veteran Omar Gonzalez jumped the White House fence and ran into the building with a knife in 2014. The same year, a toddler squeezed through the gates of the fence and was caught on the lawn.