A top US diplomat visited Burundi Wednesday for talks with officials amid deadly demonstrations against President Pierre Nkurunziza's bid for a third term.

Assistant Secretary of State for Democracy, Human Rights and Labour Tom Malinowski said in a tweet that Washington was "disappointed" Nkurunziza was not sticking by a deal reached to end the 2006 civil war.

"Not too late for leaders/ppl to stay on peaceful democratic path," he said on his Twitter account.

It was not immediately clear who Malinowski would be meeting with in the capital, Bujumbura, during his visit on Wednesday and Thursday. But acting State Department spokeswoman Marie Harf said the trip had been planned long before the protests erupted.

"He looks forward to the opportunity to talk with Burundian officials as well as other Burundian stakeholders about the current situation and ways to defuse tensions and create an environment for peaceful, inclusive, and credible elections," Harf told reporters.

Malinowski vowed to "keep the focus on rights of #Burundi ppl. We & Sec Coun made clear will be consequences for those responsible for violence."

Students expelled

Meanwhile, authorities on Thursday closed university accommodation facilities and forced thousands of students to leave the campus, witnesses said, in an operation apparently designed to halt a 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.

At least five people have died since unrest broke out at the weekend, when the ruling CNDD-FDD party designated President Pierre Nkurunziza as its candidate for the presidential election, which is due to be held in the central African nation on June 26.

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

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 constitutional court meanwhile was examining Nkurunziza's presidential campaign efforts.

The constitution says the president is elected by universal direct suffrage, for a five-year mandate that can be renewed once.
The country is also holding parliamentary elections on May 26, a month ahead of the presidential vote.

Amid threats by pro-government militias, some 25,000 Burundians have fled the country in recent weeks, according to the UN refugee agency, which has warned the numbers could rise.