E. German Talks Stall Over Secret Police Issue : Reforms: The Stasi are supposed to have been disbanded. But opposition leaders say most are still at their posts.

EAST BERLIN —  East German opposition leaders threatened Monday to break off political talks with the Communists after rejecting assurances that the hated secret police have been disbanded.

The opposition insisted that most of the secret police, the Stasi, are still at their posts around the nation even though the Communist government said two months ago that it would abolish the unit.

The opposition leaders called on Prime Minister Hans Modrow to promise that the secret police will be disarmed and disbanded.

The opposition took its stand at the weekly meeting of the so-called round table, an assembly of Communist leaders and opposition groups. The round table was established to work out procedures in advance of national elections scheduled for May 6.

Unless Modrow can provide firm assurances that the secret police are being broken up, the opposition said, it will refuse to attend next week’s meeting and will call for nationwide demonstrations.

Ingrid Kueppe, a representative of New Forum, the largest of the opposition movements, said she has not been convinced by government assurances that the secret police will be abolished before the May elections and not be replaced by any similar organization.

After the meeting, the opposition said in a joint statement that it “protests energetically against the behavior of the government.”

In a related development, about 100,000 people marched Monday through Leipzig chanting “Down with Communists” and calling for German reunification, news agencies reported.

Speakers at the rally said they fear a resurgence of Communist power and believe that the Stasi are still active. Leipzig has been the scene of regular rallies for months. Monday’s was the first of the new year after a Christmas-season break.

Peter Koch, a government official who has been involved in the move to disband the secret police, said all the agency’s personnel have turned in their weapons. He said these “have been secured” and that “any access to them by security police is out of the question.”

Koch said that 25,000 of the secret police agency’s employees have been dismissed and that its network of informers has been dissolved. He admitted, however, that 60,000 people are still working for the agency.

“We are only at the beginning of the process of disbanding,” he said.

Rolf Henrich of New Forum suggested that Koch should not accept secret police promises that their weapons were turned in.

“We are not dealing with a girls’ boarding school,” he said. “You have to be naive to think this organization will show any interest in its own breakup.”

In a related development, Konrad Weiss, a leader of the opposition group Democracy Now, told the West German newspaper Bild that the Communist regime is only now calling attention to neo-Nazi activity in East Germany.

The movement has existed for years, Weiss said, but the Communists have sought to minimize this fact in order to avoid embarrassment. “Neo-Nazis in East Germany didn’t fit in with the pretty facade,” he said.

Weiss said there are as many as 1,500 neo-Nazis in East Germany, many of them members of the secret police. He said the Communist regime is playing up neo-Nazism now as a way of suggesting that the secret police are still needed.

“They are trying to give the impression,” Weiss said, “that there have been neo-Nazis only since the Stasi went, but they were around before.”

Meanwhile, East German border guards turned back Franz Schoenhuber, leader of West Germany’s far-right Republicans party, when he tried to cross from West Berlin.

Schoenhuber’s Republicans have announced plans to establish a branch of the party in East Germany and to make German reunification their major objective.

Schoenhuber, a member of an SS formation in World War II, said that his being refused entry is “scandalous.”

“It shows how afraid this collapsing state is,” he said, “in the face of the authentic anti-Communist alternative--the only one so far--that the Republicans represent.”