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. Navy's Fifth Fleet, told Reuters: "A U.S. army major saw a rubber raft run into the ship, causing the explosion."
He said the destroyer, commissioned in 1996 and armed with standard missiles and torpedoes, had been refueling in Aden when the explosion occurred at 12:15 p.m. Bahrain time (0915 GMT).
Asked if the explosion was a deliberate attack, he said: "We don't know why a rubber raft would
be carrying explosives."
"The explosion was big enough to cause a 20-foot by 40-foot" (six-by-12 meters) gash in the left side of the ship along the waterline and that the vessel was listing four degrees.
In Washington, a U.S. official said terrorism could not be ruled out in the attack. "We can't rule it out but we're not ready to draw that conclusion. We're awaiting the facts."
Lieutenant Terrence Dudley from the Fifth Fleet said: "We are not labeling it as a terrorist act yet. It is still under investigation and we've not received any claim of responsibility."
Anti-U.S. sentiments are running high in much of the Arab world, including Yemen, over Washington's perceived support of Israel during two weeks of fierce Israeli-Palestinian violence.
Israeli helicopter gunships on Thursday blasted Palestinian targets in the West Bank and Gaza Strip with missiles to avenge the killing of two Israeli soldiers by a lynch mob.
Navy spokesperson Lieutenant Meghan Mariman said in Washington that the U.S. sailors were trying "very hard to keep the ship afloat", adding that the vessel was carrying about 300 people.
Dudley said: "USS Cole has been stabilized and the flooding has been contained. Luckily there have been no fires."
Yemeni officials confirmed the explosion but said it occurred inside the vessel.
"Preliminary information indicates that the explosion happened inside the ship in the supplies section," a Yemeni naval official, who declined to be identified, told Reuters.
But Dudley said: "We know it (the blast) occurred externally. An investigation is underway."
It was not immediately known if any people were aboard the rubber raft.
In Aden, witnesses said the explosion was so powerful that it rattled buildings near the port, one of the Arabian peninsula's largest. They said Yemeni security officials rushed to the port where the U.S. ship was anchored.
Witnesses saw ambulances carrying the wounded, but reporters were not allowed to approach the scene.