LUSAKA, Zambia (AP) _ A prominent Zambian politician was shot and killed Friday, the day he was to testify in a corruption case against three government ministers, his attorney said.

Paul Tembo, who quit the ruling party last month to join an opposition party, was killed by gunfire around 3 a.m. in his home, Sakwiba Sikota said.

He had been set to appear Friday before Zambia's Anti-Corruption Commission, which is investigating allegations that Finance Minister Katele Kalumba, Home Affairs Minister Peter Machungwa and Works and Supply Minister Godden Mandandi illegally used $625,000 of state money to finance a ruling party convention held April 27 to May 2.

Sikota said the killing appeared to be a political assassination.

``Tembo had a wealth of information which was going to guarantee that a good number of powerful people in the (ruling party) would be locked away in jail for their corruption and other thefts,'' Sikota said.

Tembo was instrumental in the campaign for a constitutional amendment that would have allowed President Frederick Chiluba to run for a third five-year presidential term. After months of speculation and fierce debate, Chiluba announced in May he would not run again.

Tembo quit the ruling Movement for Multiparty Democracy last month, after he lost elections to be the party's vice president by one vote.

He then joined the Forum for Development and Democracy, a new opposition party formed mainly by government ministers expelled from the ruling party after they campaigned against Chiluba running for a third term.