A Burundi Red Cross official says two protesters have been shot dead as pitched battles escalated between police and demonstrators opposed to President Pierre Nkurunziza's bid for a third term.

Red Cross spokesman Alexi Manirakiza said Thursday that a protester from the capital's Ngagara neighborhood was shot dead and another was killed in the Musuga neighborhood.

These deaths raised the number of people killed to at least 18 since the protests began three weeks ago, following the announcement of Nkurunziza's candidacy. More than 230 have been wounded.

The protests boiled over last week when an army general announced a coup which was crushed within 48 hours. Protesters say Nkurunziza's effort to run for president again is illegal because the constitution limits the president to two terms in office.