The US administration has urged Stormont politicians to seize the opportunity presented by urgent talks aimed at resolving the crisis over IRA activity.
Its special representative said all parties needed to remain constructively engaged after the British and Dublin governments announced a new round of negotiations to begin in Belfast next week.
Revelations that the IRA still exists and individual members carried out a recent murder in Belfast have shaken the political establishment.
Retired Senator Gary Hart, who represents Secretary of State John Kerry, said the US welcomed the renewed dialogue.
"In recent conversations with Northern Ireland party leaders and the UK and Irish governments, I strongly encouraged all stakeholders to come back together for intensive talks - to build trust, address remnant paramilitary activity, and resume implementation of the Stormont House Agreement.
"We urge all the parties to remain constructively engaged and seize this opportunity to find a way forward on the issues.
"The United States remains actively engaged and will continue to support this process."
The talks are planned for next week at Stormont House with Secretary of State Theresa Villiers representing London and Foreign Affairs Minister Charlie Flanagan, Dublin.
The purpose is to secure full implementation of the Agreement and to deal with issues arising from the impact of continued paramilitary activity in Northern Ireland, Downing Street has said.
The move came after the PSNI offered a new assessment of Provisional IRA activity stating that aspects of the terror organisation have gone away, its active service units do not exist any more and what remains fulfils a radically different purpose than during the Troubles.
Both the Irish Government and the Democratic Unionists support a new form of paramilitary monitoring of the ceasefires.
The breakdown in relations at Stormont reached a new low after the killing of a former IRA father-of-nine Kevin McGuigan, allegedly by former terror associates.
That murder earlier this summer caused political uproar after PSNI chief constable George Hamilton said the IRA - which was supposed to have gone away a decade ago - still exists for peaceful purposes and the shooting was carried out by individual PIRA members but not sanctioned at a senior level.
