Clashes between police and hundreds of demonstrators left dozens injured in central and southern Nepal on Monday during protests about the draft of a long-awaited new constitution, an opposition leader said.
Lawmakers tabled the draft in parliament last month after bickering parties struck an historic deal to divide the country into eight provinces, paving the way for a new federal structure.
The parties were spurred by April's devastating earthquake to reach agreement on the charter, which is intended to end years of political limbo in the impoverished country since a decade-long Maoist war ended.
But as the government on Monday began public discussions on the draft, opposition lawmakers and their supporters -- some hurling stones -- expressed anger about a lack of detail on where and how the new internal borders will be drawn.
"Clashes have occurred in several districts with hundreds of our supporters and more than 50 have been injured," Laxman Lal Karna, an opposition lawmaker protesting against the constitution, told AFP.
"The police did not allow our party workers to enter the discussion venues," said Karna, from the regional Madhesi Nepal Sadbhawana Party.
Opposition parties have repeatedly sought to draw up borders along lines that could favour historically marginalised groups including the Madhesi community living in Nepal's southern plains bordering India.
Protesters in Rautahat district, home to a sizeable Madhesi population, threw bricks and stones in brief clashes with security forces at one meeting, said local police official Bhim Dhakal.
"Police has had to respond with 20 rounds of tear gas and batons... to control the crowd and ensure a safe environment for discussions," Dhakal said.
Maoist chief Pushpa Kamal Dahal, better as Prachanda, had to be escorted to safety in Siraha district after protesters hurled stones during a discussion, said district police chief Ram Kripal Saha.
In the central district of Nuwakot a petrol bomb was thrown at Finance Minister Ram Sharan Mahat's convoy while he was en route to his constituency for public consultations, said his press adviser Gajendra Bista. No one was injured.
Lawmakers have fanned out across the quake-hit country to collect feedback on the draft constitution, which was intended to be the culmination of a peace process begun in 2006 when Maoist rebels laid down their arms and entered politics.
But political infighting confounded efforts to hammer out a deal, throwing parliament into disarray and crippling the economy.