US House Speaker Nancy Pelosi arrived in Syria on Tuesday, leading a Congressional delegation on a trip that the White House has criticized as a mistake which could send the wrong signal. Pelosi, who was met at Damascus airport by Foreign Minister Walid al-Moallem, is the highest-ranking American politician to visit Syria since relations began to deteriorate in 2003. The United States accuses Syria of interfering in Iraq and Lebanon and sponsoring terrorists - charges that Damascus denies. A White House spokeswoman has described Pelosi's visit to Syria as a "really bad idea." Pelosi, a Californian Democrat, did not make any comment on arrival and headed for a tour of downtown Damascus.