Toronto police called for massive reinforcements outside the U.S. Consulate after a demonstration with a large group of protesters threatened to turn nasty Tuesday afternoon.

Three people were arrested after a clash with police outside the downtown consulate on University Avenue, south of Dundas Street West, where as many as 150 Congolese protesters chanted in the streets.

Const. Wendy Drummond said that Congo protesters began throwing dirt at officers and swarmed a police cruiser shortly before police issued a request for all available police officers to attend the scene.

As many as 56 cruisers surrounded the protesters at one point as traffic was blocked from entering the area.

CTV Toronto's Paul Bliss said the group had started the day by peacefully protesting outside Queen's Park, before taking to the streets and marching toward the U.S. consulate.

The threat of clashes had subsided by about 2 p.m., as the group marched north toward Queen's Park.

Protest organizers told reporters that the group was protesting political injustice in the Congo's recent presidential election and demanding the international community get involved.

"We want the Canadian government to pay attention because hasn't covered the elections at all," one protester told CTV Toronto's Natalie Johnson. "We are overwhelmed by what's happening in Syria and Egypt, but we want them to pay attention to what's going on in the Congo."

The Democratic Republic of Congo held a presidential election last week, which remains in dispute. Opposition candidates have accused the incumbent President Joseph Kabila of fraud and threaten to reject the outcome of the vote.

Two men were charged after Tuesday's protests in Toronto.

Bantshi Mbakama, 45, of Toronto has been charged with unlawful assembly, attempt to forcible entry and two counts of assaulting a peace officer.

Fataki Martin, 26, of Toronto has been charged with unlawful assembly and assault.

According to reports, a similar Congo protest was being held in Ottawa and London, England.

In Ottawa, police used pepper spray on protesters and at least three people were arrested.

A similar protest had been held peacefully over the weekend.