Italian police seized seven alleged members of the Red Brigades in what appears to have been a major sweep against the terrorist organization that paralyzed Italian public life this spring by kidnapping and murdering former Premier Aldo Moro.

Three of those arrested were listed as suspects in the Moro case.

An announcement in Milan, where the seven were arrested Sunday in three separate hideouts, said the police operation had been aimed against the "structure and operational potential of the Red Brigades."

The best-known of the seven arrested was Nadia Mantovani, 28, the girlfriend of Renato Curcio, the imprisoned and convicted founder and leader of the group. She was not directly connected with the Moro kidnaping. She was in jail at the time and violated parole to go into hiding this summer.

Perhaps the most important of those picked up was Lauro Azzolini, 35, identified as one of the original members of the Brigades. In addition to being listed as a suspect in the Moro case, he was wanted in connection with the killing of the police chief of Biella, a town in northern Italy. He was also sought in connection with the murder of the president of the bar association of Turin last year and the wounding of a Christian Democratic Party official in Genoa.

A former Maoist, Azzolini was sentenced in absentia to four years this summer in the Turin trial of the Red Brigades leaders in which Curcio was the main defendent.

Another of the seven picked up Sunday, Antonio Savino, 27, pulled a gun and started shooting when two policemen tried to arrest him.

All three men were in the hospital yesterday with bullet wounds, although one of the policemen was said not to have been seriously wounded.

While a statement by Italian Interior Minister Virginio Rognoni called the Milan operation a "severe blow to the Red Brigades," if seemed implicitly to recognize that it would not necessarily cripple the organization, which is noted for its complex structure.

"I am aware," said Rognoni, "of the long path that remains ahead. . . . But this confirms the efforts that are being made to increase the state's capacity to prevent and suppress subversive violence. People can have faith in the police forces, which certainly do not deserve certain impatient and unjust criticisms."

Rognoni's predecessor, Francesco Cossiga, resigned the day after Moro's bound and bullet-riddled body was found in May in the back of a car in central Rome.

The police said there was evidence linking those picked up yesterday with the recent resurgence of terrorist violence after a lull during the summer holidays.