The impasse has stalled the highly sensitive trial that follows months of crackdowns against the opposition in the Gulf state, which hosts the headquarters for the US Navy's 5th Fleet.

Western officials and international rights groups have closely followed the two-month-old trial, which remains a major point of tension between communities in the island nation.

Earlier this month, the original defense team walked out of the trial after complaining that officials did not properly investigate claims of torture against the detainees, which include prominent human rights figures and bloggers.

Replacement attorneys selected by Bahrain's authorities told the court they cannot proceed because the suspects refuse to cooperate. Another hearing was set for Jan. 6 and it was unclear how the trial could resume without an approved defense team.

The group — 23 in custody and two charged in absentia — is accused of supporting "terrorist" cells seeking to overthrow Bahrain's government.

They are among hundreds detained as part of a sweeping offensive launched last summer against perceived threats to the state. The detentions touched off riots and rallies.

In October's national vote, an opposition bloc held onto its 18 seats in the 40-member Parliament, but did not gain enough outside allies for a majority in the house.