For the third time this year, Zimbabwe police have arrested a Cabinet minister from Prime Minister Morgan Tsvangirai's Movement for Democratic Change.

The MDC said police arrested Jameson Timba in Harare Friday on allegations he had undermined the authority of President Robert Mugabe of ZANU-PF.

A police spokesman in Harare confirmed the arrest but said he had no information on possible charges.

Timba this week accused Mr. Mugabe of lying about the outcome of a regional summit on Zimbabwe's tense political situation.

After the summit earlier this month, the South African Development Community said Zimbabwe must create a political environment that includes “a level playing field” for elections.

International leaders and human rights officials have accused Mr. Mugabe's party of harassing and attacking MDC supporters.

Mr. Mugabe's ZANU-PF party entered into a power-sharing deal with the Mr. Tsvangirai's MDC following violence-plagued elections in 2008. But progress has been slow and uneven and the state of the unity government remains fragile.

Timba is the third MDC Cabinet minister to be arrested in the last four months.

Authorities arrested National Healing and Reconciliation Minister Moses Mzila-Ndlovu in April, after he attended a memorial service for the victims of the Gukurhundi massacres.

An estimated 20,000 civilians died when troops loyal to President Mugabe cracked down on protesters in the western part of the country in the 1980s. There has never been an official government report or discussion on the massacres.

In March, police arrested Energy Minister Elton Mangoma on charges of corruption.