The loyalists have held nightly demonstrations since pro-Irish nationalist councillors voted last month to end a century-old tradition of flying the British union flag every day over Belfast City Hall.
The flag's removal unearthed deep discontent among loyalists, who complain of feeling left behind by political changes since the 1998 Good Friday Agreement brought an uneasy end to three decades of sectarian conflict that cost some 3,600 lives.
Some protesters turned out in the snow on Friday, but for the fourth consecutive night there was no outbreak of violence. More protests are planned this weekend, including two afternoon rallies outside the city hall in central Belfast.
Fighting broke out on Saturday as mainly Protestant loyalist protesters passed a Catholic nationalist area on their way home from a rally in the city centre.
A small explosive device posted to a senior police officer was intercepted on Friday at a post office in the west of the province, police said.