A key opposition leader in Nepal has been transferred from house arrest to police detention, his party says.
Mr Nepal has been under house arrest for over two months
Madhav Kumar Nepal was taken away by military police after they raided his house in Kathmandu, his Communist Party (Unified Marxist-Leninist) said.
Mr Nepal was placed under house arrest two months ago. Supporters say he has been taken away for a further three months imprisonment north of the city.
The authorities told the BBC that they knew nothing of Mr Nepal's whereabouts.
A number of opposition leaders and activists have been arrested in recent months for taking part in pro-democracy demonstrations against the king.
King Gyanendra sacked the multi-party government and took direct control in February 2005.
Mr Nepal is the leader of Nepal's second-biggest party, which until recently was in favour of the monarchy.
Opposition parties want the king to restore democracy
He spent a long period under house arrest following the king's coup last year.
According to his party, a group of armed policemen raided his house on Wednesday without producing a warrant and seized telephones, a fax machine and a computer.
No reason was given for the raid, which human rights groups and opposition parties have criticised as a breach of privacy.
Mr Nepal's party called his detention a "barbaric act by an authoritarian regime". A former deputy prime minister, Madhav Kumar Nepal is a senior leader of the seven-party opposition alliance that has led protests against the king.
Earlier this week, the United Nation's top human rights official in the kingdome expressed dismay at what he called the arbitrary detentions of Mr Nepal and nine others.