Speaking after talks with the central African nation's president, senior US diplomat Tom Malinowski yesterday said Washington could impose targeted sanctions over the crisis.
Unrest broke out in Burundi on Sunday, after the ruling CNDD-FDD party designated President Nkurunziza as its candidate for the next presidential election, which is due to be held 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.
"The current situation is very, very dangerous, and that some of the measures that have been taken, including in recent days, to shut down social media, to suspend radio stations not only are wrong as a matter of principle but very counter-productive," he added.
He said that Washington hoped for "a stepping back from repressive measures", and said it was "still not too late to resolve these problems and to move forward on a path of dialogue and democracy".
At least seven people have so far been killed in the protests.
Three were killed on the 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, according to the Red Cross.
A Burundi soldier was also shot dead on Thursday when an intelligence officer opened fire near a barricade erected by protesters, a police official said.
His supporters maintain 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.
