After three protesters were reported killed in the Syrian city of Deraa on Friday, U.N. Secretary-General Ban Ki-moon called on Damascus to refrain from violence.
Syrian authorities have stepped up arrests of dissidents since the Arab uprisings began in January. The deaths Friday came in Syria's most violent response to the demonstrations.
"The United States strongly condemns the violence that has taken place in Syria today and calls on the Syrian government to allow demonstrations to take place peacefully," White House National Security Council spokesman Tommy Vietor said. "Those responsible for today's violence must be held accountable."
"The United States stands for a set of universal rights, including the freedom of expression and assembly, and believes that governments, including the Syrian government, must address the legitimate aspirations of their people," Vietor said.
Ban, in a statement from a spokeswoman, said using lethal force and making arbitrary arrests of peaceful demonstrators was unacceptable.
"The secretary-general urges the Syrian authorities to refrain from violence and to abide by their international commitments regarding human rights," the statement said.