A Zimbabwean court rocked Zimbabwe's unity government on Tuesday by sending back to prison a group of civic and political activists charged with attempting to overthrow President Robert Mugabe.

The 18 activists, including members of the Movement for Democratic Change (MDC), a partner in the government, had earlier been released on bail.

"Today’s ruling seriously threatens not only the life and health of the inclusive government, but its longevity and durability," the MDC said in a statement.

The ruling was made in "flagrant disregard" of agreements by the parties forming the government, the MDC added. The party said the decision signalled that "some elements" withing Mugabe's Zanu-PF party are opposed to the unity government.

On Monday, prosecutors asked the Harare Magistrate's court to revoke bail.

The MDC said the magistrate had ruled on Tuesday that because a trial date had been set in the High Court, she no longer had
jurisdiction to extend the bail.

The MDC characterizes the charges of banditry, terrorism and insurgency faced by the activists as "trumped-up".

The 18 activists include Jestina Mukoko, a human rights activists who was among a group abducted and secretly detained by state agents last year.