The U.S. government on Monday strongly protested the alleged harassment of U.S. Special Envoy to the Great Lakes Region of Africa Tom Perriello by authorities of the Democratic Republic of Congo (DRC).

The United States is "outraged and deeply disturbed by the physical obstruction and verbal aggression" aimed at Perriello while he was departing from the Kinshasa N' djili Airport on Sunday, U.S. State Department spokesman John Kirby said in a statement.

"The U.S. Government protests this treatment of its Envoy in the strongest possible terms," the statement said.

While in Kinshasa, Perriello held meeting with a wide range of government, opposition, civil society, and international actors to encourage participation in a dialogue aimed at reaching consensus on holding a presidential election as soon as technically feasible, Kirby said.

The U.S. believes that any individuals who are responsible for perpetrating violence or repression should be held accountable, and remains ready to impose additional targeted sanctions, he said.

At the same time, Kirby expressed disappointment at the DRC electoral commission' s failure to announce an elections calendar Monday as called for by the constitution.

Moreover, Washington is "deeply alarmed by reports of violence that occurred alongside civic protests" in Kinshasa, which reportedly resulted in the deaths of protesters and police, the spokesman said.

Kirby said the latest events "underscore the need for a truly inclusive dialogue process aimed at reaching consensus on holding presidential elections as soon as technically feasible and guaranteeing the country' s first democratic transition of power."

At least 17 people, including three policemen, were killed Monday in heavy clashes between protesters and police in Kinshasa.

Police fired teargas to disperse protesters who marched in the capital against President Joseph Kabila's perceived step to extend his mandate, demanding that presidential elections be held on time.

According to its constitution, the DRC is scheduled to hold its presidential election on Sept. 20. However, the electoral commission said the election has to be postponed until a voter registrar is completed, which the opposition rejects.

Source : XINHUA