The authorities in Nepal are reported to be clamping down severely on dissent, following King Gyanendra's move on Tuesday to take direct power.
The king vows to restore democracy within three years
There are accounts of students being fired on in one town, and of numerous arrests of potential demonstrators around the country.
The media is under to total censorship with armed troops stationed in television news rooms.
The king says the moves are needed to protect Nepal from its Maoist rebels.
The rebels, who control substantial rural areas of the country, are fighting for a communist republic.
Phone lines and internet links remain cut, so news of a strike called by the Maoists has not reached the public.
'Sound of shooting'
The BBC's Charles Haviland in the capital, Kathmandu, says it is becoming clear that as the king, backed by the army, tightens his grip on power, sources of dissent are being ruthlessly blocked.
Nepal's national human rights commission says that after students demonstrated in the central town of Pokhara on Tuesday, the army raided their hostel at around midnight.
The commission says crying was heard from inside amid the sound of shooting and that it believes many students had been injured.
At least 250 students were believed to have been detained.
Regional BBC reporters who have crossed into India to file reports say 21 leaders of Nepal's biggest party, the Nepali Congress, were arrested in the western town of Kanchanpur.
The party's general secretary was being held in another western town and many district-level party leaders were taken into custody in eastern Nepal.
Other human rights sources told the BBC that nearly 70 people were being detained at armed police force headquarters in Kathmandu.
Reports critical of the state of emergency declared on Tuesday have been banned for six months, according to a notice in the main daily newspaper.
Our correspondent says that at one major newspaper house, 19 army officers have been checking articles word for word, while armed troops are in attendance at the sister television station next door.
Talks or else?
The king's new government has told the rebels to return to talks or face other measures.
NEPAL IN CRISIS
June 2001 - Gyanendra is crowned king following royal massacre
July 2001 - Sher Bahadur Deuba becomes prime minister following Maoist violence
Oct 2002 - King Gyanendra sacks Deuba and assumes executive power
June 2004 - Deuba reappointed prime minister in place of Surya Bahadur Thapa
Feb 2005 - Deuba sacked, king assumes direct power
On Wednesday, a spokesman for the Maoists ruled out any possibility of talks with the king.
It is not clear what the king has in mind if the rebels fail to re-enter peace negotiations.
The rebels had refused to hold negotiations with the last government, saying they needed a direct dialogue with the king.
Now they have condemned the clampdown.
The king's moves have been criticised by the UN, the US, the UK, India and rights groups.
He says he had to act as the government failed to protect Nepal from the Maoists.
Meanwhile, the US state department has advised American citizens against travelling to Nepal.
A planned summit of South Asian leaders was postponed on Wednesday, after India pulled out mainly because of concerns at the turmoil in Nepal.