Two opposition politicians and two journalists have been freed from detention after being acquitted of defaming Zambia's former president, Frederick Chiluba.

The charges were dropped a day after current President Levy Mwanawasa urged parliament to lift Mr Chiluba's immunity, so he can be prosecuted for alleged corruption.

[The] revelations by President Mwanawasa... call for firm action against the culprits

Times of Zambia

Mr Mwanawasa provided details of more than $50m which he said had gone missing during Mr Chiluba's time in office.

He became president last December and was initially seen in some quarters as Mr Chiluba's protege but the two camps have recently split.

As the anti-corruption probe widens, Zambia's Ambassador to the United States, Atan Shansonga, has been arrested, reports the French news agency, AFP, quoting a spokesperson for the Anti Corruption Commission.

He was reportedly arrested hours after being named in some of the documents presented by Mr Mwanawasa.

On Thursday, Foreign Minister Katele Kalumba resigned amidst allegations of corruption.

'Tug-of-war'

While many Zambians have welcomed Mr Mwanawasa's move, the BBC's Penny Dale says there was a small, vocal group of Chiluba supporters outside court.

Opposition politicians, Edith Nawakwi and Dipak Patel, and journalists, Fred Mmembe and Bivan Saluseki, were arrested last year after The Post newspaper published an article referring to Mr Chiluba as "a thief" while he was still in office.

The judge on Friday said that he did not want a "tug-of-war" with parliament, now that the issue was before MPs.

Edith Nawakwi is now free

Our correspondent says that parliament is expected to debate lifting Mr Chiluba's immunity when it reconvenes on Tuesday.

Mr Chiluba has not yet made any public comment on the allegations.

Newspapers have welcomed the move against the former president.

"Yesterday's revelations by President Mwanawasa... call for firm action against the culprits," thundered an editorial in the government-owned Times of Zambia newspaper.

"When a government undertakes a job like the one President Levy Mwanawasa's administration has to deal with a tandem of thieves that has looted national coffers, it deserves our support," added the privately-owned Post newspaper, which is normally critical of the government.

Mr Mwanawasa's allegations against Mr Chiluba and his aides include:

• $47m was "not accounted for" during the privatisation of Roan Antelope Mining Corporation (Ramcoz)
• $20.5m was allegedly paid for weapons which never arrived
• Several millions were allegedly paid to his family and cronies from a special bank account