Some protesters covered their faces and threw eggs at soldiers
The Prince of Wales's Canadian tour has been interrupted by protests from Quebec separatists.
More than 100 demonstrators held a protest that led to scuffles with police outside the regimental hall of The Black Watch of Canada in Montreal.
Prince Charles's arrival at the hall to present new regimental colours was delayed by 40 minutes as a result.
Quebec is known for its anti-monarchist views, with many people objecting to the Queen being Canada's head of state.
The protesters chanted: "Majesty go home... the Quebecois in Quebec."
Some covered their faces and threw eggs at soldiers leaving the regimental hall.
'Symbol of power'
Canadian riot police used their shields and batons to push protesters down a side road, and the prince and Duchess of Cornwall were able to enter the hall by the front entrance.
Julien Gaudeau, a spokesman for the militant nationalist group Reseau de Resistance du Quebec, which organised the protest, said: "The prince is important as a symbol of power given by the blood.
The protests meant the prince was 40 minutes late
"We don't want this kind of symbol in Quebec, more than 80% of the population in Quebec is opposed to the monarchy.
"In every other province, despite the numbers being low [in the polls] they are still pro-monarchy, the only one that isn't is Quebec, that's just one more reason for us to separate."
Prince Charles, who is Colonel-in-Chief of the The Black Watch regiment, apologised for being late and praised the legacy of his regiment.
He told the audience of senior military officials and friends and family of the regiment: "First of all I just wanted to say how very sorry my wife and I are to have kept you all waiting so long - I hear there's a little local disturbance."
A Clarence House spokesman said: "Their royal highnesses have been made to feel very welcome throughout their visit to Canada, including meeting many well wishers here in Montreal."