 Several people were injured in the clashes, including the mayor of La Paz, who turned up at the demonstrations to appeal for calm. The two left-wing politicians used to be close friends and allies, but they've been fighting over their rights to represent the governing mass party in the presidential poll. Relations have deteriorated further since Mr. Morales accused Mr. Arce of staging a coup two weeks ago, when hundreds of soldiers encircled government buildings for a couple of hours.