The DUP, the main Unionist party in Northern Ireland, has endorsed a deal to return to power-sharing government, leader Sir Jeffrey Donaldson has said.
He said it provided a basis for the return, subject to new legislation being passed in parliament, and final agreement on a timetable.
The party has boycotted government at Stormont for nearly two years.
But Sir Jeffrey faced criticism from some in the party, who spoke against the deal at an executive meeting.
The DUP collapsed the Northern Irish Assembly nearly two years ago in protest against post-Brexit trade arrangements.
The party has been in talks with the UK government to change the arrangements agreed in the UK-EU Windsor Framework deal.
Sir Jeffrey said the legislation agreed with Westminster would "remove checks on goods moving within the UK and remaining in NI, and end NI blindly following EU laws".
He added: "There will be legislation protecting the Acts of Union, which guarantees unfettered access for Northern Ireland business to the rest of the UK."
Regardless of who forms the next UK government, these measures will be taken as "legislative commitments", he said.
Monday night's meeting lasted more than five hours and was plagued with security issues. Despite the remote venue being kept secret, senior DUP members were confronted by protesters holding placards calling them "sell-outs".
The meeting was itself live-tweeted from inside by loyalist blogger Jamie Bryson, who claimed it was beset by arguments and chaotic scenes.
Nevertheless, the DUP leader said the vote had been "decisive" and that he had been mandated to operate on that.
"We will only be able to move after the government faithfully delivers on the implementation of its legal and other commitments," Sir Jeffrey told reporters.
"Both our party officers and party executive have mandated me to move forward.. on the basis of the proposals brought forward by the government, subject to and on the basis of the government delivering measures of that package."
The specific details of the deal have yet to be published but Sir Jeffrey said he was "confident" in the progress he had achieved.
And he said he believed the government could move "quickly" to bring forward legislation to implement what has been agreed with the DUP.
He also responded to posts by Mr Bryson's claims about the meeting on Twitter.
Sir Jeffrey said the reports did not reflect what happened in the room, and described that as a misrepresentation.
"But it disappoints me there may have been someone in that meeting who may have been prepared to share information," he said.
"No one tonight in our meeting at any stage or in meetings of my party officers has ever used the word betrayal but it was used tonight to describe someone who was leaking information from a private meeting."
Chris Heaton-Harris MP, Secretary of State for Northern Ireland, said: "This is a welcome and significant step.
"I am grateful to Sir Jeffrey Donaldson and colleagues for the constructive dialogue over the past months and to the other political parties in Northern Ireland for the patience they have shown during this time.
"I am pleased that the DUP have agreed to accept the package of measures that the UK government has put forward and as a result they are ready to return to the Northern Ireland Assembly and nominate representatives to the Northern Ireland Executive.
"Sir Jeffrey Donaldson has said this is subject to the binding commitments between the Democratic Unionist Party and the UK government - I can confirm that we will stick to this agreement.
"I now believe that all the conditions are in place for the Assembly to return, the parties entitled to form an Executive are meeting tomorrow to discuss these matters and I hope to be able to finalise this deal with the political parties as soon as possible."
'Political stability is vital'
The largest party in the most recent election was Sinn Féin. Party leader Mary Lou McDonald said she was "optimistic".
"It is vital there is political stability to address the scale of the crisis across our public services," she said.
"Let's now focus minds on the job at hand and to the solutions required to support workers and families who want and deserve functioning government."
Sir Jeffrey said he gave his word to trade unions that pay awards to public sector workers would be prioritised when the institutions were restored.
However, Davy Thompson of the Unite union said said there was not enough for the unions to call off strike action on Thursday "because we don't know when that government will be formed".
"Until there is government in Northern Ireland, there is no government in Northern Ireland."
Traditional Unionist Voice (TUV) leader Jim Allister, Baroness Kate Hoey, Ben Habib and Jamie Bryson jointly published a paper setting out their opposition to any deal.
Reacting to Monday night's news, Mr Allister tweeted that the DUP had "caved in in betrayal of their own solemn pledges".
