Nepal braced Monday for months of political instability and street protests after a midnight deadline passed without agreement on a new constitution, triggering fresh elections.
Prime Minister Baburam Bhattarai said the country's political leaders had failed to achieve their goal since their election four years ago and he said a new vote would be held in November.
"We have no other option but to go back to the people and elect a new assembly to write the constitution," Bhattarai said in his announcement broadcast live over television.
The government put security forces on high alert and riot police were patrolling the streets of the capital, Katmandu, though there were no reports of violence Monday, police spokesman Binod Singh said.
Police clashed with protesters Sunday outside the Constituent Assembly, where political leaders from the country's four main parties had been meeting in a last-minute attempt to agree on a new constitution before the deadline. The key sticking point was whether the states to be created by the constitution should be determined on the basis of ethnicity.
Thousands of protesters opposed to the idea tried to push through a riot police line on the northern side of the assembly hall Sunday. Police pushed them back and a scuffle ensued, with the protesters throwing stones and police responding with tear gas and batons. Three policemen and several protesters were injured.
On the other side of the assembly hall, thousands of people demonstrated in support of states based on ethnicity. A thick police line kept the opposing groups apart.
The Constituent Assembly was elected to a two-year term in 2008 to draft a new constitution but has been unable to finish the task. Its tenure has been extended four times, but the Supreme Court rejected any further extensions.
The assembly's formation came two years after pro-democracy protests forced Nepal's king to give up his authoritarian rule and restore democracy in the country.
One of the assembly's first decisions was to abolish the centuries-old monarchy and convert Nepal into a republic.
The political parties have been able to resolve some other thorny differences in the past, including the future of thousands of Maoist rebel fighters who were confined to camps after giving up their armed revolt in 2006. However, they have not been able to agree on the ethnic issue.
The prime minister said he would be leading a caretaker government until the Nov. 22 elections.
At least two of the country's main political parties — Nepali Congress and Communist Party of Nepal (United Marxist Leninist) — have vowed to take to the streets in protest.