ROME (AP) _ Hundreds of police searched the homes of suspected terrorists and sympathizers overnight looking for the killers of an air force general who was shot by two men on a motorcycle, authorities reported today.

Anti-terrorism police were posted around government buildings and key intersections. Police also searched cars at roadblocks around Rome, officials said. No arrests were reported.

Gen. Licio Giorgieri, 61, was killed Friday evening in a fusillade of pistol fire as he rode in his car. An anonymous caller claimed responsibility on behalf of a leftist group believed linked to the Red Brigades, which orchestrated a reign of terror in the late 1970s and early 1980s.

Giorgieri was an engineer in charge of buying and maintaining arms and aircraft, said Cmdr. Francesco Di Mento, a Defense Ministry spokesman. Italian newspapers said today he was known in military circles as ''the Star Wars expert,'' a reference to the U.S. program for developing a space-based missile defense.

An autopsy showed the general was shot twice in the neck and twice in the left shoulder with one bullet piercing the left ear, police said.

Premier-designate Giulio Andreotti condemned the assassination as ''a barbarous and evil act.''

Interior Minister Oscar Luigi Scalfaro called a meeting of top anti- terrorism officials today. It was the second attack in Rome claimed by left- wing terrorists in five weeks. The Red Brigades claimed responsibility for the Feb. 14 ambush of a mail truck in which two police were killed.

About an hour after Friday's attack, an anonymous woman caller to the Milan office of the Rome newspaper La Repubblica said in a statement:

''This evening we took care of Licio Giorgieri, the top man in charge of constructing arms and air force and space armaments. Fighting Communist Union.''

The ANSA news agency said the Fighting Communist Union is believed to be a splinter group of the leftist Red Brigades.

''The Red Brigades continue to operate,'' news agencies quoted Defense Minister Giovanni Spadolini as saying after the killing.

The attack ''constitutes a new blow in the plan launched to destabilize the country, a plan which will find, on the part of the state, a firm and decisive reply,'' Spadolini was quoted as saying.

Giorgieri was shot in Rome's Aurelia neighborhood, about 3 miles from the historic heart of the capital.

The general's chauffeur told police that just before the attack he looked in his rearview mirror and saw a motorcycle flashing its headlight, news reports said. The driver said he pulled over to let the motorcycle pass.

Two youths pulled the motorcycle alongside the general's car and fired pistols, then the man on the rear of the motorcycle got off and fired more shots at the general, news reports said. The killers then sped off.

Giorgieri was dead on arrival at a hospital, police said.

The driver, who was not identified and was uninjured, was quoted as saying Giorgieri regularly took that route home.

Police set up roadblocks in an attempt to block the killers' escape and were examining a motorcycle found nearby to see if it was used in the attack.

Referring to the terrorist attacks that plagued Italy a few years ago, Spadolini said, ''The killers are back among us. ... General Giorgieri was chosen as a most notable example of men in uniform who work for the defense, that is the independence and sovereignty of the country.''

In March 1978, the Red Brigades kidnapped former Premier Aldo Moro north of Rome and killed five bodyguards. They demanded the government free jailed leftist terrorists. The government refused, and 55 days later Moro's bullet- ridden body was found in a car in Rome.

In December 1981, U.S. Brig. Gen. James L. Dozier was kidnapped by the Red Brigades. Police stormed his kidnappers' hideout six weeks later and freed him uninjured.

Spadolini later said Dozier's liberation marked ''the beginning of the victory'' against terrorism.

But there since have been several assassinations linked to the group, including the 1984 killing of Gen. Leamon Hunt, the American head of the multinational peacekeeping force in the Sinai, and the 1986 killing of a former mayor of Florence, Lando Conti.

The Fighting Communist Union claimed responsibility for an attack in February 1986 that injured Antonio Da Empoli, a former economics adviser to the government.