EAST BERLIN (AP) _ Authorities on Thursday arrested a former Politburo member under investigation for corruption and abuse of power and put him in prison to await trial, along with seven other ex-leaders.

Communists and opposition groups held their eighth round of talks, with the opposition demanding a role in dismantling the hated secret police force.

The opposition also demanded the right to speak in Parliament.

Negotiators unanimously approved a resolution calling on Communist Premier Hans Modrow to give them periodic written updates on the dissolution of the secret police force, which is to be dissolved by June 30.

The negotiators also called on the secret police to turn in their guns, grenades and other weapons by the end of this month.

The imprisoned ex-official was identified as Hermann Axen, who was once the Communist Party's top foreign policy representative.

Axen, 73, was jailed after returning from an eye operation in Moscow, the official ADN news agency said, quoting government authorities.

Seven other members of the disgraced regime of Erich Honecker also are in prison awaiting trial on charges they abused their positions of power.

ADN said authorities found additional evidence against Honecker, who was forced from office Oct. 18, and against former Politburo members Guenter Mittag and Erich Mielke.

Mittag, the former economics czar, is blamed for the nation's industrial slump, while Mielke headed the secret police. They are in prison.

Honecker is hospitalized after undergoing an operation last week to remove a kidney tumor. He and Mielke are expected to be tried for high treason.

The latest threat to Modrow's coalition government appeared to have been defused, at least temporarily. Christian Democratic leader Lothar de Maiziere said his threat on Wednesday to quit the government was ''premature.'' A final decision is expected soon.

De Maiziere had complained the Communists held too much power.

Modrow has appealed to his coalition partners to hold the government together until the nation's first free elections less than four months from now, spokesman Wolfgang Meyer told a news conference in East Berlin.

''The government is standing firm in its responsibilities,'' Meyer said.

Strikes and demonstrations have kept up the pressure on the government, while boosting opposition forces before the May 6 balloting.

The New Forum opposition group opened Thursday's negotiations with a call to maintain the ''peaceful revolution'' that has swept the country since October.

It also demanded full access to documents regarding the secret police. Government officials say the number of agents and informants was nearly 200,000.

In presenting the resolution, New Forum representative Reinhard Scult called the secret police ''a danger to development of society, and a danger to internal peace.''

The secret police force, known as the ''Stasi,'' used strong-arm methods to suppress dissent during the Honecker era.

Negotiators Thursday asked that former Communist Party leader Egon Krenz be forced to reveal comprehensive information about the secret police when he appears before the panel next week.

On Wednesday, Krenz cited an oath of secrecy in refusing to divulge such information to a commission investigating the brutal tactics used by police to disperse pro-democracy protests Oct. 7-8.

Honecker has denied responsibility for the brutality, but on Wednesday ousted Politburo member Guenter Schabowski said Honecker was to blame.

''Honecker took things into his own hands,'' Schabowski said. ''All decisions and orders that led to the police actions against demonstrators and to their arrrest went exclusively through Honecker and Mielke.''