Mrs Foster rejected the Secretary of State's claims, saying: "This letter fails to deal with the fatal flaws in the Withdrawal Agreement.
"Indeed, it doesn't even address the flaws raised by the Attorney General.
"Rather than writing letters or sending a roadshow to NI for 90 minutes, I would prefer the PM would go to Brussels and stand up to the EU and seek fundamental changes to the Withdrawal Agreement," Mrs Foster said.
"This deal breaches key commitments made to us, by the Prime Minister, about protecting the economic and constitutional integrity of the United Kingdom.
"The Chancellor says the backstop is bad for the economy and Union.
"The PM doesn't like it and the Attorney General has warned Cabinet that it's a trap.
"Unionists in Northern Ireland and throughout the UK are united against this dangerous deal.
"This letter won't fool anyone who has read the Withdrawal Treaty."
PMs deal is fatally flawed and has to be renegotiated, insists DUP leader - BelfastTelegraph.co.uk
renegotiating Brexit deal is 'a delusion"
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