Pubdate: 7/23/97 CARACAS (Reuter) Venezuela and the United States signed an agreement Wednesday allowing authorities from either country to board boats carrying the Venezuelan or U.S. flag on the high seas if they were suspected of carrying drugs. The agreement was signed by U.S. ambassador to Venezuela John Maisto and the Venezuelan Foreign Minister Miguel Angel Burelli. Maisto said the agreement broke ``a new boundary in U.S.Venezuelan cooperation in the fight against drugs.'' On Tuesday, Venezuelan authorities seized a Panamanianregistered tanker with more than five tons of cocaine in a joint operation with the U.S. Drug Enforcement Agency. 19:25 072397