Honduran soldiers have used truncheons, tear gas and rubber bullets to disperse thousands of supporters of ousted President Manuel Zelaya.
Mr Zelaya has taken refuge at the Brazilian embassy in the capital, Tegulcigalpa, since his surprise return from exile on Monday.
Security forces are patrolling the area around the embassy in the capital following clashes with the former president's supporters, the BBC reports.
Mr Zelaya accuses interim authorities of "asphyxiating" the embassy by cutting off supplies.
Brazil's president has warned against any action being taken on the embassy.
Interim leader Roberto Micheletti has denied any action is planned, and has urged Mr Zelaya to turn himself in.
The US, Brazil and other governments have joined Mr Zelaya in calling for a negotiated settlement to the crisis.
A curfew has been imposed, airports shut and roadblocks set up on highways leading into Tegucigalpa.