BONN, NOV. 27 -- East Germany's Communist authorities cracked down on the nation's small, Protestant church-linked dissident movement this week by temporarily detaining several dozen activists and seizing duplicating machines used to produce two newsletters that reported on environmental, disarmament and human rights issues.

The government's actions, in East Berlin and several smaller East German cities, were the toughest measures used against critics since the early 1980s, West German government specialists said.

The steps may be a result of recent indications from Moscow that the reform program of Soviet leader Mikhail Gorbachev has run into trouble, the experts said. The East German leadership has been among the most steadfast opponents in Eastern Europe of Gorbachev's policy of glasnost, or openness.

The government also may have wished to dampen dissidents' hopes that the government would tolerate increased public dissent in the wake of the unprecedented visit to West Germany of East German chief of state Erich Honecker in September, western analysts said.

The crackdown began with a raid late Tuesday night on the "environmental library" in a basement room of the Zion Church in downtown East Berlin. Security agents detained seven persons and confiscated documents and equipment used to produce the low-circulation newsletters.

One of the bulletins, called "Environment Page," concerns pollution issues. The other, called "Borderline Case," focuses on political topics and is published by the dissident Peace and Human Rights Initiative.

On Wednesday, more than a dozen persons were detained at the Zion Church when a crowd of about 150 gathered to protest the raid, according to church sources quoted by West German media reports. Activists also were detained and questioned in Dresden, Rostock and Halle, they said.

Authorities released all but two of the detainees by yesterday evening. They did so after talks between church leaders and Hermann Kalb, deputy state secretary for church matters.

The raid marked the first time since the 1950s that security officials have searched the premises of an East German church, according to East Berlin Protestant officials. East Germany's Protestant church provides rooms, other logistical support and, indirectly, protection for the nation's small dissident movement. The church is the only organization in the country that is both influential and independent of the Communist Party.

Kalb said the authorities acted as part of an investigation into the "formation of groups to pursue illegal objectives." East Germany's official news agency ADN reported yesterday that seven persons were caught at the church "in the act of producing subversive material." In an apparent attempt by authorities to avoid a confrontation with the church, the agency said the detainees had acted "behind the backs" of church officials.

Several hundred protesters were maintaining a vigil outside the Zion Church to call attention to their demands for freedom for the two remaining prisoners, who were not identified, and for the reopening of the "environmental library."

This morning, firemen removed a protest banner from the church's tower. A church official, the Rev. Hans Simon, said authorities told him this afternoon that the dilapidated church may be shut down for safety reasons.

In West Germany, the government and all political parties strongly protested the East German actions.

"The action of the East German authorities is surely a sign that neither freedom of speech nor of the printed word is allowed," Dorothee Wilms, minister for intra-German relations, said.

Her deputy, Ottfried Hennig, said the East German authorities "used a sledgehammer to crack a walnut."

East Germany has serious environmental problems, especially air pollution caused by the burning of soft coal. Environmental activists charge that the government does not provide sufficient data about the issue.