President Bolanos could also see his immunity removed

Senior officials, including the interior minister, went before the Inter-American Human Rights Commission to denounce the opposition-led move.

The US-based commission said it would consider sending a team to Nicaragua.

A struggle between congress and the president has been worsening, despite international efforts to mediate.

Nicaragua's Central American neighbours and the Organization of American States have expressed their concern over the crisis.

Liberal anger

Two ministers and three senior officials have been stripped of their immunity from prosecution so they can be investigated for alleged campaign funding irregularities.

"This is a coup d'etat in slow motion. It is a coup d'etat that is happening in different stages and parts." Nicaragua's ambassador to the US, Salvador Stadchagen, said.

"The first step was for [former President Arnoldo] Aleman and [Sandinista leader Daniel] Ortega to kidnap the legislative and electoral powers and now they are going after a part of the executive branch.

"If they could, they would also seek to completely occupy the executive office," the diplomat said

President Enrique Bolanos also faces having his immunity removed by the opposition-controlled congress.

Members of his own Liberal Party have turned against him - and joined forces with the Sandinistas - angered by his government's decision to prosecute former President Aleman for corruption.

Mr Bolanos took office in 2002 after a landslide victory over Mr Ortega.