A statement from the Peoples Party of Malaysia (PRM) said that three of its leaders and a member of the Democratic Action Party (DAP) were released on police bail after several hours of questioning.

Senior leaders

The men - PRM deputy president Abdul Razak Ahmad, its youth wing chief Hassan Abdul Karim, deputy secretary Mohd Salleh Ahmad and DAP member Chan Choke Lam - were arrested on Thursday evening in the southern city of Johor Baru.

The authorities have made no comment. In a statement, PRM president Syed Husin Ali welcomed the release, but strongly condemned the arrest.

He said the four might be charged under the Police Act for illegal assembly.

He added the men were arrested "without warning" for distributing the pamphlets informing people about the "need for genuine reform".

Wan Azizah Wan Ismail launches reform group

But he did not say whether the leaflets were linked to the new reform group launched by Wan Azizah Wan Ismail, the wife of sacked former deputy prime minister, Anwar Ibrahim.

Mrs Azizah announced on Thursday that she was setting up a national organisation to press for political, economic and social reform.

She said the group - the Movement for Social Justice - was a response to the Malaysian people's demand for justice.

Anwar Ibrahim denies sex and corruption charges

She stressed it was not a political party but said it would work with two opposition coalitions which were formed shortly after her husband's arrest.

Mr Anwar was sacked in September. He was later arrested and charged with sex and corruption charges, which he denies.

He is currently facing trial in Kuala Lumpur's High Court.

Since September, hundreds of political activists have been arrested in Malaysia for joining demonstrations supporting Mr Anwar and opposing Prime Minister Mahathir Mohamad.