Amir Junos, a former Deputy Chief of Police Intelligence, was giving evidence for the prosecution at the trial of Mr Anwar.

The prosecution is trying to prove that he abused his power last year by forcing police to arrest and obtain retractions from those who had written to the authorities about his alleged sexual misconduct.

The head of the police intelligence unit made a similar allegation in the opening stages of the trial.

Mr Anwar has said the charges of corruption and sexual misconduct are part of a political conspiracy against him.

New twist

Riot police have been stationed outside the court

Mr Anwar's trial took a surprise turn when the chief prosecutor was called as a witness in a separate criminal case.

Reports say the defence had subpoenaed Deputy Public Prosecutor Abdul Gani Patail to testify on Thursday in the trial of a former tennis partner of Mr Anwar, Nallakaruppan Solaimalai, accused of illegal possession of live bullets.

Mr Anwar's lawyers declined to give more details about the subpoena, but correspondents say its purpose is to try to prove government lawyers had improperly pursued the ammunition case against Mr Anwar's friend in hopes of improving their chances of having Mr Anwar convicted.

Anti-government protests

The Anwar trial is at the core of unprecedented anti-government unrest in Malaysia.

Anwar says he is the victim of a high level political conspiracy

Last Saturday hundreds of anti-government protesters demonstrated in his support in the capital, Kuala Lumpur.

Police used water cannons to disperse the demonstrators who were calling on Prime Minister Mahathir Mohamad to resign.

Mr Anwar's supporters received an unexpected boost from US Vice President Al Gore who said that Washington had "heard the brave people of Malaysia" in their calls for "reformasi" (reform).

His comments at the start of the Asia Pacific Economic Co-operation (Apec) summit last week outraged ministers who said he was making unwarranted interference in Malaysia's internal affairs.

BBC South East Asia Correspondent Simon Ingram says the Malaysian opposition fears a government crackdown on Mr Anwar's supporters.