As the US Secretary for State Hillary Clinton travels to Northern Ireland on Friday, Northern Ireland First Minister Peter Robinson called on protesters for calm. Loyalist protesters' demonstrations over the lowering of the Union flag over Belfast City Hall turned violent earlier this week.

Anti-sectarian Alliance members of the regional assembly at Stormont and Westminster have been targeted at their homes and offices by arsonists, vandals, and pickets. These attacks follow the decision to reduce the number of days the union flag would be flown above city hall.

On Monday night protests outside the council meeting turned ugly. Golf balls, bottles, and crush fencing were thrown at police officers.

Protesters plan another mass demonstration on Saturday, one of the busiest shopping days of the year, and there are fears that there will be a risk of violence in the city center.

Will Kerr, Police Service of Northern Ireland (PSNI) assistant chief constable told “To encourage thousands of people to come to Belfast city centre on one of the busiest days of the year would be madness.”

Read more: Loyalist protest turns violent as Belfast lowers Union Jack- VIDEO

Robinson said, “My advice is that street protests should be suspended by those responsible for organizing them in the wider interests of a peaceful society and to ensure their protests are not used by others to launch a campaign of violence.

“Britishness will not be progressed by acts of violence. Anyone engaging in wanton violence or intimidation does not defend our national flag but disgraces it.”

On Wednesday night unrest spread to other area in Northern Ireland. In Carrickfergus, County Antrim, 1,000 rioters burned down the office of Alliance MLA Stewart Dickson. Four police officers were injured.

In Bangor, County Down, arsonists attempted to set fire to the office of Stormont Employment and Learning Minister Stephen Farry. Also the windows at the home of two Alliance councillors with a 17-month old baby were damaged.

Chief Constable Matt Baggott warned politicians not to engage in dogma over flag issues, making matters worse. He pointed to the tolerance of Queen Elizabeth and met with Robinson to ask him to help cool tensions.

Read more: Protests over Union Jack in Belfast play out like a movie with too many sequels – VIDEO

He said, “Loyalism can never be an excuse to compromise democracy, to use mob rule and violence as a way of asserting people’s will and compromising the rule of law, and I call upon people to take a step back. There is far too much at stake for the future and for the here and now.”

Sinn Fein Deputy First Minister Martin McGuinness said, “This is an attack on the democratic decision taken in Belfast City Hall by those who are democratically elected to represent the people of this city.”

Ireland’s deputy prime minister, Tanaiste Eamon Gilmore, said this violence should stop. He said, “Such violent attacks on a democratic party are an attack on democracy itself. They are reprehensible and have no place in a civilized society.”

Here’s raw footage posted online on Wednesday