LUSAKA, Zambia (Reuters) - A Zambian High Court judge barred the government Tuesday from declaring a winner in the closely contested presidential election until he had ruled on an opposition appeal Wednesday.

Judge Peter Chitengi is hearing a petition from 10 opposition parties that the ruling Movement for Multiparty Democracy (MMD) rigged last week's presidential, parliamentary and municipal polls.

``No action whatsoever should take place before my ruling on this matter tomorrow at 8.30 a.m. This a very important case. It is urgent and it is of national importance,'' Chitengi told reporters in his office.

Chitengi earlier abandoned his courtroom after police clashed with thousands of opposition supporters outside the High Court. The protesters were demanding the court nullify the polls.

The latest results from the Electoral Commission, with almost all the votes counted, showed ruling party candidate Levy Mwanawasa ahead of his closest rival, businessman Anderson Mazoka.