A U.S. general kidnaped from his home in the northern city of Verona is being held in a "people's prison" and will be tried according to "proletarian justice," an anonymous caller today told an Italian news agency in Verona.

The Red Brigades terrorist group has claimed responsibility for the abduction of Gen. James Lee Dozier, 50, the senior U.S. Army officer in NATO's southern Europe command. Four men dressed like plumbers broke into Dozier's roof-top apartment yesterday and carried him away at gunpoint. They gagged and tied up his wife and left her in the apartment.

[In Washington, President Reagan called Dozier's captors "cowardly bums" and said the United States was doing everything it could to secure his release. "They aren't heroes, or they don't have a cause that justifies what they're doing," the president said. Details on Page A12.]

No immediate demands have been made for Dozier's release.

Despite a vast police dragnet throughout much of northern Italy, police were unable to find any trace of the general. They located a blue Fiat van, rented in Milan, that they believe was probably used by a commando unit of as many as 10 terrorists in the kidnaping.

The unidentified caller said the kidnaping had been organized by the "Venetian Column" of the Red Brigades and that branches of the Marxist group from Milan, Naples and Rome as well as Venice had participated in the kidnaping of the "hangman." The message gave no indication of why Dozier was called a "hangman."

[Pentagon sources said the Defense Department sent a six-member team to Rome to serve as liaison with Italian authorities investigating the kidnaping, but the Defense Department declined comment, The Associated Press reported.]

Italian Prime Minister Giovanni Spadolini said after a meeting this morning with his government's defense and security experts, that the kidnaping "is certainly a qualitative jump in the strategy of terrorism."

Leftist Italian terrorists began operating in Italy 10 years ago, but the unexpected operation yesterday was the first against a military officer and the first against a foreigner.

It was also the first time that Italian terrorists moved against a NATO base here and appears to represent a shift toward the anti-American, anti-NATO tactics that West Germany's Red Army faction terrorists have followed.

Although spokesmen at the NATO base in Verona said Dozier's function as deputy chief of logistics and administration of the integrated NATO command was primarily administrative, press accounts have speculated that the terrorists holding him will seek to extort secret information regarding the deployment of troops and military supplies in Italy and Europe.

[Joe Favorite, a NATO spokesman, said such a motive would be more plausible if the victim were in operations, intelligence or communications, AP reported.]

Most of the Italians who have been kidnaped by the Red Brigades so far -- judges, politicians and business executives -- are said to have "cooperated," writing frequent letters to government authorities, possibly under dictation.

One executive who police believe did not cooperate, petrochemical plant manager Giuseppe Taliercio, was killed early last summer. But cooperation also does not ensure survival, as became evident when former prime minister Aldo Moro was slain after writing scores of letters to political friends and foes during his 54 days of captivity in 1978.

Furthermore, although it is far too early to tell what, if any demands the terrorists might make for the release of the general, an embassy spokesman today said that in previous occasions in other parts of the world the United States has said it will not negotiate with terrorists.

Judith Dozier, the general's wife, appeared briefly on Italian national television.

One of her cheeks was badly bruised. But she seemed calm and spoke in a steady voice in English to reassure friends and relatives.

"Mom and Dad, please stay calm," she said. "I just want to let all our friends in the United States know that I am fine."