Jailed ex-deputy premier Anwar Ibrahim entered the third day of a hunger strike today but his wife said he would take fluids in a Muslim-style fast for health reasons.

Anwar began refusing food late Sunday in solidarity with six of his supporters who launched a hunger strike on April 10, the first anniversary of their detention without trial under the Internal Security Act (ISA).

The six are pressing to be tried in open court or released. They are accused of planning to use violence to topple Prime Minister Dr Mahathir Mohamad.

Anwar's wife, Wan Azizah Wan Ismail, said prison officials had persuaded her husband to avoid total fasting, warning that it was detrimental to his health, particularly as he had a dose of flu and a prolonged back disorder.

"After some coaxing, he said he will not back off his strike but will go on a Muslim fast. He will not eat anything until sunset, after which he will just have milk and water with his medicine," she told AFP .

Wan Azizah, who met Anwar earlier today after he was taken to a government hospital for a medical check-up related to a slipped disc, said she was worried about her husband's well-being.

She said Anwar had been put on antibiotics for his flu and now had problems with movement of his left foot due to his back injury, allegedly caused by a police assault after his arrest in 1998.

"He has not showed much signs yet. I am worried because I don't know how long it would go on but Anwar is a very determined person and he is concerned about the detainees," she added.

The six detainees, who are being held at a detention camp in Kamunting in Perak, were in the seventh day of their hunger strike Tuesday with no plans to quit, an opposition official told AFP .

Wheelchair bound

Earlier today, Anwar arrived in a wheelchair and smiled to journalists before being escorted into the hospital by police guards for a medical examination.

The hunger strike came ahead of a visit by Mahathir next month to the White House, his first since 1994, where the veteran Malaysian leader is expected to be thanked for his support to the US-led war on terror.

Washington has however, made it clear that Mahathir's upcoming visit has not altered the US view that Anwar, who is serving a total of 15 years in jail on corruption and sodomy charges, is a political prisoner.

Visiting US Assistant Secretary of State James Kelly said yesterday that the US government was firm in its stand that Anwar's trials "were very political in nature" and hoped his appeal cases would be handled "fairly and transparently".

Critics say the charges against Anwar were trumped up to prevent a political challenge to Mahathir, who has been in power for 20 years. The government denies this.

The government has remained silent on the hunger strike.