LUSAKA, Zambia (AP) _ Riot police wielding batons and shields prevented pro-democracy campaigners from meeting Saturday to establish Zambia's first legal opposition party in 17 years.

Paramilitary units stood guard outside the Moon City Night Club in the Zambian capital, barring hundreds of would-be party delegates from entering.

The legal committee of the so-called Movement for Multi-Party Democracy, which called the meeting, immediately filed an injunction with the High Court against the police.

But High Court Judge Bobby Bwalya postponed the hearing for a week so officials from the movement and from President Kenneth Kaunda's ruling United National Independence Party could testify.

There was no immediate comment from the government.

Kaunda, 66, who led Zambia to independence from Britain as a Western-style democracy in 1964, imposed a one-party state in 1973.

Last month, under mounting pressure from lawyers, students, trade unionists and businessmen, Kaunda agreed to rewrite the constitution to legalize opposition parties.

Earlier, he legalized the pro-democracy group and announced multiparty elections would be held next August to allow his 7.5 million people to decide what political system they want.

But police refused to issue a permit for Saturday's conference, despite earlier government assurances that opposition groups could hold meetings.

Levi Mwanawasa, head of the movement's legal committee, told 400 supporters at the group's headquarters that the meeting had to be canceled because of the police blockade.

''We are not going to give up,'' chairman Arthur Wina, a former Kaunda loyalist and onetime Cabinet minister, told the gathering. ''But our patience is running out. We're being pushed against a wall.''

In the central Copperbelt province mining city of Kitwe, the Zambian Congress of Trade Unions passed a motion Saturday calling for Kaunda's resignation.

Similar calls for Kaunda to step down have been made since rioting over increased food prices in July left at least 26 people dead.

Opponents accuse Kaunda of corruption, mismanagement, authoritarianism and nepotism.