Hillary Clinton will welcome Northern Ireland leaders Peter Robinson of the Democratic Unionist Party and Martin McGuinness of Sinn Fein to the United States in mid February, where plans for an economic development conference for Northern Ireland will be put together.

In addition, the White House announced that both McGuinness and Robinson will be at the White House on St. Patrick's Day to meet with President Obama and discuss the ongoing American role in the Irish peace process.

The American open-arms welcome comes after the two parties agreed a way forward in Northern Ireland after 10 days of gruelling negotiations.

It emerged yesterday that Secretary of State Clinton was deeply involved in the final days of the negotiations and had numerous calls with the key players on both sides, as well as the British and Irish governments.

The plans for the economic development conference are expected to be announced after the meetings in Washington with Robinson and McGuinness. A conference in the fall in Washington is among the ideas being presented, in addition to further high profile visits to Northern Ireland by the US special envoy Declan Kelly.

Speaking after the announcement of the breakthrough Clinton said the US was ready to help.

"The people of Northern Ireland are poised to build a thriving society on this stronger foundation," she said.

"Our economic envoy, Declan Kelly, will continue working to help Northern Ireland reap the dividends of peace, including economic growth, international investment, and new opportunities.

"In the near future, Declan and I will host First Minister Robinson and Deputy First Minister McGuinness here in Washington.”

In his statement President Obama said the agreement, reached by the Democratic Unionist Party (DUP) and Sinn Fein on the devolution of policing and justice power from London to Northern Ireland, "is an important step on the pathway to greater peace and prosperity for all communities on the island."

Taoiseach (Irish Prime Minister) Brian Cowen said the agreement was "an essential step for peace, stability and security in Northern Ireland" which laid the foundations for a better future.

And newly reinstated Northern Ireland First Minister and DUP leader Peter Robinson said it was better to get it done and get it right.

"Over recent weeks there may have been great frustration out in the community," he said.

"But there would have been even greater frustration if we did a deal that collapsed. So it is far better that we spend the extra time and we get it right."

He said the DUP's members had unanimously backed the agreement. "This is a sound deal and one that I can recommend," he said.

McGuinness, from Sinn Fein said: "We are dealing with centuries old difficulties here.

"If we are to succeed as a government, we have to show people at grassroots level that we can work together. The last thing that we want to do, while the eyes of the world are on us, is to fail."

He added: "This might just be the day when the political process in the north came of age."

British Prime Minister Gordon Brown hailed the deal, saying the agreement was possible because of "a new spirit of mutual cooperation and respect."

"We are closing the last chapter of a long and troubled story and we are opening a new chapter for Northern Ireland," he said.

Sinn Fein leader Gerry Adams also welcomed the deal and said: "There's a wonderful chance now in a new spirit for us all to go forward."

Clinton with Martin McGuinness and Peter Robinson