The leader of the DUP has denied being pressured by US politicians to sign up to the new Brexit deal on trade for Northern Ireland.

Sir Jeffrey Donaldson told the PA news agency that the US administration and other political figures in Congress had been “very understanding” of his party’s desire to seek further assurances from the UK government following the signing of the Windsor Framework.

Sir Jeffrey held talks with US national security advisor Jake Sullivan in the White House on Thursday to discuss the framework, which is aimed at removing some of the economic barriers on Irish Sea trade created by Brexit’s contentious Northern Ireland Protocol.

The DUP is currently blocking devolution at Stormont in protest at the terms of the protocol.

While the party says the Windsor Framework has gone some way to address its concerns, it says some “fundamental problems” remain with the new accord.

Sir Jeffrey, who is in Washington to attend St Patrick’s themed events this week, is now seeking further clarity and assurances from the UK government to address his party’s continuing concerns.

MPs will vote on legislation next week that would give effect to the “Stormont brake” mechanism within the Windsor Framework. The brake would allow a minority of MLAs at Stormont to formally flag concerns about the imposition of new EU laws in Northern Ireland – a move that could see the UK government veto their introduction in the region.

Sir Jeffrey said he understood why political leaders in the US capital would like to see the institutions in Belfast restored ahead of next month’s landmark 25th anniversary of the Good Friday peace agreement.

But he said his party was focused on getting the right outcome, not deadlines.

“Well, of course, look I understand why people would want to see the political institutions up and running,” he told PA.

“But I have to be honest, I haven’t been put under any pressure during my time here in Washington. I think people are actually very understanding of the need for unionist parties in particular to assess what the Windsor Framework is, what it means, to examine the legal text and the legislation that will be used to implement that framework.

“So, I think that amongst the people I’ve talked to here, whether in the administration or on Capitol Hill, there is an understanding that it’s not about working to a particular deadline, it’s about getting it right.”

Commenting on his engagement at the White House on Thursday, Sir Jeffrey added: “We had a very good meeting with Jake Sullivan, the national security advisor, and we were bringing him up to date in terms of our approach to the Windsor Framework, the continuing concerns that we have about our ability to trade with the rest of the United Kingdom.

“We want to ensure that any new arrangements don’t put barriers in place that prevent us or restrict our ability to trade with the rest of the United Kingdom and we’ve already indicated to the Government where we have areas of concern.

“I note that the Government is bringing forward legislation next week on the Stormont brake and of course we’ll look at that and consider what our approach should be.

“But I think it’s important that we work our way through now the legislation, the legal text, so that we understand fully the detail of what this framework actually means in practice for businesses trading within the United Kingdom or trading with the European Union.”

Sir Jeffrey will be taking part in a range of engagements to mark St Patrick’s Day in Washington on Friday, culminating with a reception at the White House where he is potentially set to discuss the Windsor Framework with President Joe Biden.

“That’s an opportunity yet again to explain to people where we’re coming from, what our case is and how we intend to deal with the challenges in front of us at the moment,” the DUP leader said of the reception.

“We want to see a stable government in Northern Ireland but, fundamentally, we’ve got to deal with the problems created by the protocol. We’ve got to ensure that what is being put in place actually works for businesses in Northern Ireland and respects Northern Ireland’s place as part of the United Kingdom.”