Bolivia’s leftwing government is threatening to scupper an assembly to rewrite the country’s constitution and has lent its support to violent street protests aimed at forcing out an elected opposition regional leader, renewing concerns over President Evo Morales’s reform programme.

The assembly has been gridlocked since beginning work last August, divided over its basic voting rules. The governing MAS party, which has 137 of the assembly’s 255 seats, wants individual clauses to be approved by a simple majority, rather than the two-thirds majority vote the opposition favours.