WASHINGTON - The White House was placed on lock-down Tuesday after an air space violation was reported in the area, according to media reports.Nearby roads were closed and no one was allowed into the compound. Law enforcement officials told NBC News that an airspace violation was reported in Washington and fighter jets were scrambled. Security lock-downs are not uncommon around the White House. The U.S. Secret Service had no immediate comment.A White House official said the aircraft was not believed to be hostile. The lock-down was lifted a few minutes later.