An explosives-laden rubber raft rammed a U.S. guided missile destroyer and exploded in the Yemeni port of Aden on Thursday, killing four U.S. sailors and injuring 36, five seriously, Reuters reported. The White House said President Bill Clinton was horrified by what appeared to be a "terrorist" attack on the destroyer USS Cole. One sailor was still missing some five hours after the explosion caused a big hole on the left side of the listing vessel, the officials said. Yemeni President Ali Abdullah Saleh offered condolences to Clinton and the "friendly American people" and flew to Aden to visit some of the injured, who also included two Yemeni port workers, the official Saba news agency reported. Lieutenant-Commander Daren Pelkie, spokesman for the Bahrain-based U.S.