Hillary Clinton calls for end to violence

Limiting the number of days the flag can be shown has caused protests across the country. A loyalist mob set fire to offices of the centre-ground Alliance Party in Carrickfergus in County Antrim and the home of two councillors in Bangor was attacked.

The situation escalated as four men were arrested in Londonderry in connection with a viable bomb. Homes had to be evacuated as the army made the bomb an improvised explosive device safe.

Two men aged 47 and 49 were arrested at the scene at about 8.40pm. Two others, also in their 40s, were arrested later

A letter bomb was found in a postbox in Clough, Co Down, and defused by the Army.

A spokesman for the Police Service of Northern Ireland said they had received reports of a man acting suspiciously at a postbox at Dundrum Road at about 9pm last night.

Naomi Long, an Alliance MP, has been told to leave her home and not go to her office by PSNI who said there was a threat to her life.Ms Long, a former city councillor who won the seat at the last general election from Peter Robinson, said: "This will not prevent me providing a constituency service to the people who elected me."

The renewed hostilities come as Mrs Clinton is due to speak at Northern Irelands parliament, Stormont, and visit the new Titanic Centre later today.

She has visited Northern Ireland twice since becoming Secretary of State and held up the region as an example of somewhere that has overcome its troubles.

The Secretary of State met meet Peter Robinson, Northern Irelands first minister, in one of her last foreign trips as Washingtons most senior diplomat, before she steps down in the New Year.

Before she became part of the Obama adminstration, she was a repeated visitor to the country with her husband, former US President Bill Clinton, who was influential in the peace process.

The couple turned on the Christmas lights in Belfast in 1995 a year after the first IRA ceasefire.

The increasing tensions will be a blow to Da! vid Cameron after he agree to hold next years G8 summit near to the site of one of Northern Irelands worst bomb attacks.

The Prime Minister will welcome the leaders of the world's eight richest countries at the Lough Erne hotel and golf resort in Co Fermanagh in June.

It will take just five miles from the site of the Enniskillen bombing, which was one of the worst to hit Northern Ireland when it killed 12 people in 1987.

The summit will be the largest diplomatic event ever to be held in Northern Ireland. The Queen visited Enniskillen earlier this year during her two-day Diamond Jubilee tour and an historic meeting with Martin McGuinness.

Loyalists were today urged to cancel more planned street demonstrations in protest at the restrictions on flying the flag.

There were threats to hold another mass demonstration in Belfast city centre on Saturday, one of the busiest shopping days of the year, when many people could be at risk if violence breaks out, police said.

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

Northern Ireland First Minister Peter Robinson called on protesters to suspend their action. He said: "My advice is that street protests should be suspended by those responsible for organising 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," he said.

"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."