ADDIS ABABA (AFP) -- Ethiopia has charged 55 opposition members with trying to launch a rebellion, a government prosecutor told AFP Wednesday.

More than one hundred opposition figures are already on trial, accused of plotting a coup after disputed 2005 elections.

Most of those already on trial, as well as the 55 newly-accused, belong to the main opposition Coalition for Unity and Democracy.

"This is something different. It has to do with activities of CUD members who are in collaboration with some armed groups who want to destabilize the system," prosecutor Shemeles Kemal told AFP by telephone.

The case has "nothing to do with those who are already on trial, the defendants are different. But it can be seen as a continuation," he said.

The prosecutor accused the defendants of operating under the cover of an illegal organization called the Ethiopian People National Unity Front, according to Ethiopian state news agency ENA, quoting charges brought by the prosecution on Monday.

The trial of more than 100 opposition members has drawn deep concern from donors and criticism from rights groups that maintain the government is trying to stifle dissent in the wake of unrest following the May 2005 election that the CUD claims was rigged.