West German authorities said today they suspected leftist urban guerrillas were responsible for the early-morning killing of a state official in Frankfurt, in an attack that possibly signals a resurgence of terrorist activity following West Germany's recent waves of protest.

No group has claimed responsibility for the attack in which Heinz Karry, 61, the controversial economics minister of the southwestern state of Hesse, was shot in the stomach while in bed in his suburban Frankfurt home. Karry died as an ambulance arrived to take him to the hospital.

The federal prosecutor's office in Karlsruhe took charge of the investigation, however, saying it suspected that urban guerillas may have been involved in the murder. If true, it would mark the first leftist political killing in West Germany in four years.

A statement issued by the Bonn government said: "If this turns out to be a politically motivated murder, the government expresses its particular horror at political violence." Meanwhile, Hesse Interior Minister Ekkehard Gries said there was no doubt that the meticulously planned killing was politically motivated.

Karry's outspoken support for plans to extend Frankfurt Airport and build a nuclear fuel reprocessing plant in Hesse won him enemies on the left and among ecologists. But Karry, a former Nazi labor camp prisoner whose unconventional language and sharp humor made him among the most colorful personalities in West Germany's small but influential Free Democratic Party, always refuses police protection because, he said, he could not imagine that anyone would attack him.

Karry was also national treasurer of his party, which is a junior partner in the Bonn government coalition. Recent allegations that he was involved in irregularities with party election funds and reported arms deals brought press demands that he resign or be dropped. He failed to win reelection to the party's regional executive committee last Friday.

A number of West German officials expressed shock and anger at Karry's death. Free Democrat Party chairman and Foreign Minister Hans-Dietrich Genscher said his party had lost "an upright man who constantly set an example of loyalty to liberal beliefs and courage in defending political goals."

The last political killing in West Germany occurred in 1977 when the extreme leftist Red Army faction kidnaped and murdered Employers' Association president Hanns-Martin Schleyer. When this effort failed to win the release of three of the terrorist group's imprisoned leaders -- including group founder Andreas Baader -- the three committed suicide.

Many members of the underground organization have since been captured and jailed, but authorities say at least a dozen terrorist suspects remain at large. Recent street violence by West German youths and growing public demonstrations against nuclear power, nuclear missiles, and housing shortages have been seen by some police officials as potentially fertile ground for the sprouting of renewed terrorist activity.

Investigators said today's killing, which occurred at about 5 a.m., had apparently been carefully planned. Public prosecutor Heinz Haueisen told reporters at the scene that one or more assailants had used a ladder to climb through Karry's open bedroom window, then fired six shots at him.

His wife found the home phone disconnected when she tried afterward to phone for help, and ran to neighbors who called the police, according to West German authorities.

It was also reported that Karry had recently received a spate of anonymous telephone calls at home, apparently aimed at discovering when he was usually in his house. The last such call came before midnight last night and was taken by Karry's wife Maria, Haueisen said.

She was sleeping in the same room in a bed directly under the window at the time of the shooting, he added, but was not injured as the assasin apparently shot over her to hit the minister in a bed at the other side of the room.