Harare - The head of Zimbabwe's national trade union federation has spent two nights in a prison cell following his arrest for allegedly holding an illegal meeting, lawyers representing him said Tuesday.

Lovemore Matombo, president of the Zimbabwe Congress of Trade Unions, and two of his colleagues, Michael Kandakutu and Percy Mcijo, were arrested in the north-western resort town of Victoria Falls on Sunday for "holding a meeting without notifying police," their lawyer, Kucaca Pulu, said.

Union officials said Matombo was arrested on the first stop of a tour of the country to consult with union members.

His is the latest in a series of arrests in the last three weeks that have included the heads of the country's umbrella organization for civil society bodies, a senior human rights lawyer and an official from the Movement for Democratic Change (MDC) official who was found to have been tortured.

Manfred Nowak, the UN special rapporteur on torture, was also detained and expelled from Zimbabwe in late October, despite an invitation from Prime Minister Morgan Tsvangirai.

The MDC, Nowak and several human rights watchdog organizations have warned of a resurgence in harassment by judicial authorities and police of opponents of President Robert Mugabe.

Such incidents had dropped sharply after Tsvangirai entered into a power-sharing agreement with the autocratic leader in February.

Tsvangirai, persuaded by regional leaders, has just ended a three-week boycott of cabinet meetings with Mugabe and his ministers which he called in frustration over Mugabe's party's resistance to reforms. (dpa)