Water cannons loaded with blue dye were fired into crowds, The Guardian reported. The Police Service of Northern Ireland said the dye might serve as an identifier.
"The police will be following up things like CCTV evidence with a view to prosecutions," Northern Ireland's justice minister, David Ford, said.
The trouble began Sunday when loyalist Protestants responded violently to a republican flute band marching past an Orange Hall in North Belfast, the Belfast Telegraph said. The republican group appeared to be acting in response to a loyalist band that violated an order to refrain from playing sectarian songs while marching through Catholic areas.
On Sunday, at least 47 police were injured during 10 hours of street battles. Another nine were reported hurt Monday.
Loyalist leaders blamed "heavy-handed policing" for the disorder, while Sinn Fein, the republican party, blamed the Ulster Volunteer Force and Ulster Defense Association, two loyalist militias, for instigating the trouble.