Officials say at least a dozen people are dead amid protests over a proposed law the opposition fears will prolong the president's time in power.

Government spokesman Lambert Mende said Thursday that 12 people have died in three days of unrest and pillaging that began Monday.

But a coalition of human rights groups says 42 people were killed by security forces firing on protesters.

An uneasy calm returned to the capital Thursday, but four more people died during demonstrations in the country's east.

Lawmakers in Congo's lower house have passed a measure requiring a census before presidential elections next year.

Critics say that would in effect delay elections. The Senate adjourned Thursday before its own vote.

President Joseph Kabila, in power since 2001, is barred from running again.