Sinn Fein has said the EU would remain resolute on the Irish border backstop.
President Mary Lou McDonald met chief Brexit negotiator Michel Barnier in Brussels on Wedneday.
Europe has repeatedly said it will not renegotiate the backstop, which is designed to prevent the imposition of a hard Irish border and protect all-island trade if no better solution is found.
Unionists believe it would create a de-facto border in the Irish Sea and separate Northern Ireland from the rest of the UK.
Ms McDonald said: “Despite the chaos of Westminster and the brinkmanship of the British government it is clear that European leaders remain resolute.
“All whom we met today made clear that the Withdrawal Agreement and the backstop must remain as negotiated.
“The Taoiseach must be equally clear. He must not panic in the face of British Government threats or brinkmanship in the coming days and weeks.”
She said there was a uniformity of approach and unanimity of purpose among all she had met in Europe to safeguard Ireland’s interests, the rights of citizens and to protect its agreements.
“The EU has made it abundantly clear there can be no undermining of the Withdrawal Agreement and its backstop.
“The DUP continues to play a reckless game in its pursuit of a Brexit at the cost of our institutions, agreements and economy.
“The British government continues to attempt and placate DUP.
“The DUP is massively out of step with the majority opinion in the North in relation to Brexit, the Withdrawal Agreement and the backstop.”