A federal building near the White House was evacuated for about a half hour Friday because of a bomb scare, interrupting the White House's morning press briefing.

The White House Conference Center on Jackson Place is serving as the temporary offices of several of President Bush's press aides as well as reporters covering the president.

White House spokesman Tony Fratto had begun his 9:30 a.m. briefing for reporters when he was interrupted by Deputy Press Secretary Scott Stanzel and a security officer. Stanzel said everyone must leave the building.

A car checked by a bomb-sniffing dog had tested positive, Stanzel said. Later, Secret Service spokeswoman Kim Bruce said nothing amiss was found in the vehicle, which was driven by a State Department contractor and had been stopped at the entrance to the White House complex.

During the investigation, nearby streets were blocked off, but the White House itself wasn't evacuated.