BAGHDAD, Iraq (AP) - U.S. troops and warplanes killed 20 insurgents Saturday while destroying safehouses for foreign militants near the Syrian border, and four more American military deaths edged the war's U.S. death toll closer to 2,000.The day's heaviest fighting came when U.S.-led forces raided five houses suspected of sheltering foreign fighters in Husaybah, a town near Iraq's border with Syria, the military said. The troops reportedly killed 20 insurgents and captured one. The raiders found two caches of small arms, ammunition, rocket-propelled grenades, mortar rounds and bomb-making materials, the military said. Troops set off a car bomb found near one of the buildings, and the Air Force then used precision-guided munitions to destroy the houses.