The United States praised France yesterday for seizing a ship last weekend carrying 150 tons of arms from Libya to the Irish Republican Army, calling it "the largest terrorist arms shipment ever intercepted" and a dumb move by Libyan leader Moammar Gadhafi.

State Department spokesman Charles E. Redman said the ship carried "a wide range of weaponry," including surface-to-air missiles and automatic guns, and that it had come from the Libyan capital, Tripoli.

"We congratulate the French government" for the seizure, and "we condemn in the strongest possible terms this latest example of state-supported terrorism by Libya," Redman said.

"This shipment was destined to support further terrorist violence by the IRA. We can only deplore again this latest in a long line of examples of Libya's disregard for accepted international values and norms," Redman said.

Among the captured arms, according to U.S. officials, were Soviet-made SA7 antiaircraft missiles, mortars, rocket-propelled grenades, AK47 assault rifles, heavy machine guns and "large quantities" of explosives and ammunition.

Other news reports said the shipment included 20 Soviet-made antiaircraft missiles, 1,000 Kalashnikov automatic rifles and 40 tons of ammunition.

Redman said the ship's crew left "no doubt about both the origin and destination" of the arms.

Gadhafi has long openly declared support for the Irish terrorist group and has given it arms and money. But one U.S. official said that the massive quantity of arms and the addition of antiaircraft missiles "is a first."

U.S. officials said they were especially surprised that Gadhafi chose a time when his troops are bogged down fighting in Chad and he has been seeking to improve his strained relations with Western Europe.

"He couldn't have picked a dumber move at a worse time," said one official. "We're still scratching our heads. What did he {Gadhafi} think he was going to get out of it? A shipload of Irish whisky?"

U.S. officials are assuming the antiaircraft missiles indicate the IRA was contemplating shooting down British military or civilian planes, action that would represent a major escalation.

State Department officials yesterday still had received few details about what Redman described as an operation carried out "entirely in the hands of French officials" and with no U.S. assistance.

According to a report Monday in The Manchester Guardian, French customs officials seized the Panamanian-flagged ship, the Eksund, off the coast of Brittany last weekend after a month-long surveillance operation that involved French and British authorities.

The Eksund's last port of call was in Malta, and British intelligence agents there had tipped off the French, who kept the ship under surveillance from the air for three days as it skirted French territorial waters, The Guardian said.

French customs officials boarded the ship just as its five-man crew, all with Irish passports, were trying to escape in a rubber boat.

Meanwhile, the Defense and State departments announced yesterday that the United States has begun supplying Stinger antiaircraft missiles to Chad and has sent a team there to train the Chadians on their use. Pentagon sources said the United States is sending seven launchers and 24 missiles at a cost of about $2 million.

Redman said the United States, which provided $34 million in regular and special military aid last fiscal year, is sending Stingers because one of "the primary threats" to Chadian forces is Libyan planes.