DAMASCUS, Syria (AP) - Syrian President Bashar Assad on Thursday challenged the basis of U.S. sanctions on his country and said he would not expel Palestinian militant groups as demanded by the United States. Assad disputed the case the Bush administration had made to impose the embargo, saying Syria does not have weapons of mass destruction and there is no evidence of foreign fighters crossing the border from Syria to Iraq. "We have always asked the administration to give us one passport or one name or evidence of that (border infiltration) happening. So far, we have not had that happen,"...