Violent clashes broke out in Burkina Faso’s capital Ouagadougou after a second day of protests denouncing the president’s plan to seek re-election.
The political crisis spilled out onto the streets in a campaign of civil disobedience called by the opposition.
Blaise Compaore, who came to power in a coup in 1987 and has won four presidental elections since then, aims to amend the constitution so that he can run for office for another three terms.
The country’s parliament is due to vote on Thursday on whether to hold a referendum allowing the change.
Burkina Faso is a key ally of the US in West Africa in the fight against al-Qaeda-linked fighters operating in the region. Washington said it was “concerned by the spirit and intent behind” the amendment.