Police in the Nepalese capital, Kathmandu, have clashed with huge crowds demanding changes in the government of King Gyanendra.
Police used force to disperse the demonstrators
Some 25,000 people are estimated to have taken to the streets in a second day of protests.
At least 50 people were injured when police took action to prevent marchers approaching the royal palace.
There has been political deadlock in Nepal since last year, when the king assumed executive powers.
King Gyanendra dismissed the government in October, saying it was failing to deal with the long-running Maoist rebellion in which thousands of people have been killed.
The coalition of parties which then found itself in opposition has been in confrontation with the king ever since.
Police on Friday used batons and tear gas to disperse the demonstrators.
The opposition parties said that one of their workers was critically injured after a bullet hit him. Senior leaders, including some former ministers, were among the injured.
"When they moved towards the restricted area, the security and riot police started using water cannons and charged with batons to disperse the protesters," one of the demonstrators, Pramod Mishra, told the AFP news agency.
The protests were in contrast to a relatively good-natured rally on Thursday, when tens of thousands of people staged the biggest rally since the king's controversial assumption of executive powers.
The king is at present in western Nepal, visiting areas affected by the Maoist rebellion.
The king has just suggested new elections within a year, but protesters say that is impossible in the current violent climate - they say an all-party government should be formed first and direct talks with the Maoists initiated.