President Obama will meet NI leaders on St Patrick's Day in Washington
US President Barack Obama has hailed the Northern Ireland policing deal as "an important step".
The president will meet First Minister Peter Robinson and Deputy First Minister Martin McGuinness in Washington on St Patrick's Day.
Policing and justice powers could be devolved to NI on 12 April following the deal between the DUP and Sinn Fein.
A cross-community vote on devolving the powers will be held in the NI Assembly on 9 March.
President Obama will also host the Irish Prime Minister Brian Cowen at the White House on 17 March.
He said he appreciated the contribution of Mr Cowen and Gordon Brown to the agreement, which he called "an important step on the pathway to greater peace and prosperity for all communities on the island".
Agreement was struck late on Thursday night after a meeting of the Democratic Unionist Party Assembly team.
Every MLA present backed the deal just before midnight.
Mr Brown, who arrived in NI on Friday, said 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.
Disagreement on the timing of the devolution of the justice powers had threatened to collapse Northern Ireland's power-sharing administration.
Mr Cowen said the deal was "an essential step for peace, stability and security in Northern Ireland" which laid the foundations for a better future.
DUP leader Mr Robinson said: "Over recent weeks there may have been great frustration out in the community.
"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."
Mark Devenport, BBC NI political editor
The five sections of the deal
The first on policing and justice will set a date of 12 April as date for the devolution of policing and justice powers. It will also deal with the operational independence of the chief constable.
Secondly, a working group to look at reforming the regulation of parades will be set up. That group will report back within a month with a view to getting legislation to the Assembly by June.
Thirdly, there will be details laying out the relationship between the Justice Minister and the rest of the Executive.
Fourthly, there will be a commitment to tackle the "dysfunctionality" of the Executive. The two ministers from smaller coalition parties, the SDLP and UUP, will take the lead in this.
Fifthly, there will a move to free legislation which has become "trapped" in the system.
Sinn Fein's Mr McGuinness 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."
A round table session of the assembly to discuss the deal took place on Friday morning attended by the two prime ministers.
the Ulster Unionist Party did not attend
it because it was not told what the agreement contained before it was made public.
Party leader Sir Reg Empey said he would be seeking clarification form Mr Brown on the document.
He refused to say whether the UUP would take part in planned discussions about a new justice minister on Monday.
It had been expected that the parties would offer the justice ministry to the cross-community Alliance but the UUP chief whip Fred Cobain said his party would not accept such a move.
The normal procedure of electing ministers using the D'Hondt mechanism would give the ministry to the SDLP and Mr Cobain said acting outside D'Hondt was "gerrymandering".
He added: "We have been trumpeting this for months. We think the Alliance party have prostituted themselves over the issue of the justice ministry for months.
"We are not in favour of gerrymandering anything and we won't support Alliance because they have no democratic right."
The DUP agreed to back the deal after 10 days of talks with Sinn Fein, the British and Irish prime ministers and other parties on the issue.
The deal was announced at Hillsborough Castle on Friday
The deal was also welcomed by Alliance Party leader David Ford: "This is what the people of Northern Ireland have waited so long to hear and it means that the Executive can get back to the real work of providing quality services and strengthening our economy."
SDLP leader Mark Durkan said he always thought a deal would be "scrambled over the line".
"We will have to take our turn with other parties in proofing what is proposed, not trying to create problems, but pre-empting any possible shortcomings or problems there are with it so we can actually improve it."
However, Traditional Unionist Voice, which opposes mandatory coalition with Sinn Fein, described the DUP as "snowmen who had melted".
Its leader Jim Allister said: "The DUP MLAs who buckled not only let themselves down, but, more importantly, let their country down."
Referring to the fact that 14 DUP assembly members reportedly voted against a deal on the table on Monday, he added: "The deal the DUP so meekly accepted is the same deal they rejected.
"The deal hasn't changed, only the snowmen of the DUP who melted once the heat came on."
The relationship between Sinn Fein and the DUP has been strained for some time because they disagreed about the timetable for the transfer of policing and justice powers from Westminster to Stormont.