Occupy DC protesters are believed to have thrown a smoke bomb onto the White House grounds during a protest in the American capital last night.
The US Secret Service confirmed the incident to local Washington television and have opened an investigation.
No arrests were made at the march.
The incident locked down the president’s residency for a few hours, preventing journalists from the White House press pool from leaving the building.
President Obama was out celebrating his wife Michelle’s 48th birthday with their two daughters.
Earlier on Monday, 2,000 demonstrators converged upon Capitol Hill to stage a rally against what they see as the corrupting influence of corporate cash over the country’s politicians.
Four people were arrested at the so-called Occupy Congress protest.