At least nine protestors were hurt in Burundi's capital Thursday in renewed clashes over a bid by the country's president to stand for a third term, the Red Cross said.

The national organisation confirmed that the overall death toll from days of violent protests now stands at six dead.

Three were killed on a first day of protests on Sunday — when police were accused of firing on demonstrators — and three later that night in an alleged attack by ruling party militia forces.

The nine people injured on Thursday included several who suffered gunshot wounds, Burundian Red Cross spokesman Alexis Manirakiza said. A military source confirmed that police had again fired on groups of demonstrators.

Unrest broke out after the ruling CNDD-FDD party designated President Pierre Nkurunziza as its candidate in the next presidential election, which is due to be held in the small central African nation on June 26.

Opposition figures and rights groups say that Nkurunziza's attempt to stand for a third consecutive term goes against the constitution as well as a peace deal that ended a civil war in 2006.

Authorities on Thursday closed university accommodation facilities and forced thousands of students to leave the campus, witnesses said, in an operation apparently part of efforts to halt the wave of protests.

Large numbers of students, many of whom come from rural areas, could be seen evacuating the University of Burundi, situated in the capital Bujumbura, after the government order was issued overnight.

The authorities have already cut mobile access to several social networks and messaging applications including Twitter, Facebook and WhatsApp, which have been used to coordinate protests.

The president, a former rebel leader and born-again Christian from the Hutu majority, has been in power for two terms since 2005.

His supporters say he is eligible to run again, since his first term in office followed his election by parliament — not directly by the people as the constitution specifies.