BARCELONA, SPAIN, DEC. 27 -- A U.S. serviceman died today of injuries received in a grenade attack on a USO club here yesterday that left nine others wounded, and rival Catalan separatist groups said they carried out the attack. Police said they doubted the claims.

Navy Seaman Ronald Strong, 22, of Reeders, Pa., died at the Hospital del Mar early today of shrapnel wounds suffered in Saturday's attack, the fourth this year on U.S.-linked facilities in Barcelona.

The U.S. Embassy said none of the nine other victims had life-threatening wounds in the afternoon attack on the club, which was crowded with sailors on shore leave.

Three other servicemen, identified as Daniel Powell, Wayne Andrews and Randy Corner, were released from the hospital today, and doctors expected Todd Ringwelski, suffering ankle injuries, to leave the hospital within 24 hours. Five others returned to their ships, the destroyer Beary and the frigate Thorn, which were on a Christmas call at Spain's biggest port.

Two Catalan separatist organizations -- Terra Lliure (Free Land) and the little-known Catalan Red Liberation Army -- telephoned news media to claim the attack. Catalonia is a wealthy and nationalistic region of northeastern Spain with its own language and culture.

{A caller claiming to represent the Catalan Red Liberation Army repeated the group's claim to have bombed the U.S. consulate earlier this year, The Associated Press reported.} The group, which has also claimed attacks on the offices of Hewlett-Packard and General Electric in Barcelona earlier this year, later asked Terra Lliure to withdraw its claim for the USO attack.

Police said they had no evidence the claims were authentic, and the U.S. Embassy said there was no clear indication of who was responsible. Police were investigating a report that a man, described as an Arab or a mulatto, fled after the attack.

They said two grenades hurled into the bar were Italian- or American-made but provided no clue. "Anyone could have this stuff," a spokesman for the provincial governor said.

Barcelona residents said anti-American graffiti were daubed recently on walls near the bar.

{In Washington, State Department spokesman Ben Justesen said, "We are saddened and angered that unarmed and off-duty sailors celebrating the holidays were attacked by terrorists. We extend our deepest sympathy to the families, shipmates and friends of the one American sailor who died of his wounds and the nine other U.S. sailors who were wounded in the attack."

{U.S. officials were arranging air transport to return Strong's body to the United States, according to an AP report citing EFE.

{Mary Ann Vance, owner of the Reeders General Store, said the death upset the small community in the Pocono Mountains of east-central Pennsylvania. Strong was married this year and his wife is expecting a child next spring, said Robert Bryson, a cousin who lives in Reeders.

{"He was a very good boy, a nice boy, clean cut," said Vance, adding that Strong had been in the Navy about 1 1/2 years.}