Three police officers were injured and a police revolver containing six rounds of ammunition lost during sectarian rioting in north Belfast on Sunday night.
Some 200 nationalists and loyalists gathered in the North Queen Street area, pounding police and British army units with stones and fireworks. A vehicle was set alight at Spamount Street, in the nearby Catholic New Lodge area.
A PSNI spokeswoman said the police weapon was "mislaid" after officers came under attack in Spamount Street.
A Sinn Féin councillor, Mr Gerard Brophy, accused the police of heavy-handed tactics, while the party's North Belfast MLA, Mr Gerry Kelly, said loyalist involvement in the riots made "absolute nonsense" of the Loyalist Commission's "no first-strike" policy.
A 65-year-old man, meanwhile, suffered head injuries when he was attacked by a number of men with a meat cleaver as he was walking his dog in nearby Duncairn Gardens. His condition is not thought to be life-threatening.
In south Belfast, six people have moved out of a student house following a blast bomb attack. The device, which contained nails, was thrown into a downstairs bedroom of the Tate's Avenue house shortly after midnight on Monday.
Three people in an adjoining room had to be treated for shock. The house's occupants, who are of mixed religion, blamed loyalist paramilitaries. The SDLP's Further Education Minister, Ms Carmel Hanna, described it as a "case of attempted mass murder", while a Sinn Féin councillor, Mr Stiofán Long, said it clearly had a "sectarian motivation".
The UUP Culture Minister, Mr Michael McGimpsey, called on Queen's University to take full responsibility for first-year student accommodation, with the Workers' Party describing the incident as a "barbaric act of savagery".
The Student Union's president at the university, Mr John Mackell, said the attack could not be allowed to pass without the "strongest condemnation".