KUALA LUMPUR, Malaysia - In an investigation with serious implications for Malaysia's democracy, police on Wednesday detained another former aide of sacked finance minister Anwar Ibrahim in connection with investigations into a sex-and-treason case. Anwar, a popular and powerful figure, was sacked last month after alleging corruption in high places and challenging the handling of the Asia economic crisis.

Federal police criminal investigation director Yaacob Mohd Amin said Mohamad Azmin Ali, Anwar's former private secretary, would be held for a week under the Penal Code.

"It's a normal procedure for us to call someone and then detain him if we think necessary to help us in our investigations," he said.

This is the fifth arrest in connection with allegations of sexual misconduct, treason and corruption of Anwar's associates. As is often the case in Malaysia, the nature of the alleged corruption and sexual misconduct has been kept quiet by the authorities.

Anwar, the deputy prime minister and heir-apparent to Prime Minister Mahathir Mohamad, has said that the arrests were part of a campaign to incriminate him and foreshadowed his own arrest.

Mahathir, who has made a career raising objections to western "interference" in Asia, tuned on Anwar after his aide raised questions about Mahatir's refusal to face up to Malaysia's economic troubles.

Malaysia has weathered Asia's financial crisis better than most of its neighbors. But for several months, Mahatir refused even to acknowledge that the country would go into recession - an implicit admission that Malaysia is, after all, dependent on the rest of the world economy for its own prosperity.

The ugly split between the two has taken on the appearances of a power struggle.

Besides the arrest of Anwar's personal secretary on Wednesday, four others have been arrested under Malaysia's Internal Security Act, which allows detention without charges. Those in custody include Anwar's adopted brother, two former secretaries and a Pakistani who worked as a speechwriter for Anwar.

Sacked Malaysian deputy prime minister Anwar Ibrahim speaks at a media conference held at his house in Kuala Lumpur.

On Tuesday, Anwar likened the police action in arresting his former aides and friends to those of the Israeli intelligence services - not a favorable comparison in the predominantly Muslim country.

"His (Mohamad's) family members were warned not to inform anybody - his lawyer, me, or any member of my team. I don't know what kind of system (they are operating under) - the Shabak or Mossad?" the New Straits Times newspaper on Wednesday quoted Anwar as telling reporters.

Federal police chief Abdul Rahim Mohamad Noor said on Wednesday that Anwar's remarks were most unacceptable.

"If it was indeed true that Anwar has likened the police investigations to that in Israel, the police just feel so uncomfortable as the word Israel is regarded as extremely sensitive by the people and in the country," the official Bernama news agency quoted Abdul Rahim as saying.

"If Anwar has stated that the police are using the law of the jungle in investigating allegations against him, I can understand that, considering the mental state he is in at the moment," he said.

The police inspector-general said late on Tuesday that Anwar would be arrested if he continued to hold public assemblies without a permit.

"If there is no permit he cannot (hold assemblies)," Abdul Rahim said. "As a former cabinet member, he should know the law."

Anwar, who was sacked on September 2 and expelled from his political party one day later, has been holding meetings at his suburban home in Kuala Lumpur which have drawn thousands of people. Police have not intervened although permits have not been granted.

Anwar said on Tuesday that he expected to be arrested after the Commonwealth Games, which end next Monday.

Britain's Queen Elizabeth was scheduled to arrive in Kuala Lumpur on Sunday and stay until September 23.