"I object in the strongest possible terms to people who have limited experience of the Troubles in Northern Ireland throwing threats of violence around as some kind of bargaining chip in this negotiating process", said Mrs Foster - a thinly veiled rebuke to former prime ministers Tony Blair and John Major, who have raised the prospect of civil war in Ulster as a pretext for reversing or watering down Brexit.
Mr Barnier added that it was a "rather surprising idea" to think the European Union could accept convergence in some areas "and at the same time open up the possibility for divergence when there is a comparative advantage to be had" for the UK.
"We need to receive specific proposals from the U.K.", Juncker told a plenary session of the Parliament in Strasbourg during a speech to MEPs in which he repeated his demand for "clarity" from the British government.
"I'm clear there is a difference between those people who came prior to us leaving and those who will come when they know the United Kingdom is no longer a member".
The European Union would make the point before EU leaders meet at a summit on March 22-23 that the EU was a long-standing and trusted security partner of the United States and thus not a threat to national security and that the Pentagon only needed 3 percent of USA annual steel production to serve its needs.
"To do so is an insult to the people of Northern Ireland who worked so hard to bring peace to our country", she added. If you made a decision to jettison, leave behind, the common agreements and rules then you have to accept that things can not remain what they are ...
Sen. Elizabeth Warren Isn't Running For President in 2020
Figures on sexual assault against Native American women vary but the issue is agreed to be serious. She said "no one" could take that away from her. "And never used it for anything".
He has put forward a motion to the European Parliament for an "association agreement" to deal with the future UK-EU relationship.
Companies in Britain and the European Union face an extra 58 billion pounds ($80 billion) in annual costs if there is a no-deal Brexit, with Britain's vast financial sector set to be the worst-hit industry, according to a report on Monday.
European Commission Vice President Valdis Dombrovskis told the same news conference he has not seen any financial instability due to Brexit, and an orderly departure remains the baseline scenario.
Two senior European Union diplomats told Reuters that Brussels would wait until Britain itself has taken a view on how to respond before making any policy moves of its own.
He recently said in an interview that "sceptics" to such a deal were wrong, and that it would be "in our mutual interest" to establish a free trade agreement when Britain leaves the European Union next year.
He said: 'Mrs May, we did not vote for a transition period, we voted to leave this organisation, we voted to leave the customs union, we voted to leave the single market.