Senior DUP MP Sammy Wilson has branded Donald Tusk a "devilish, trident-wielding, euro maniac".
Mr Wilson, the party's Brexit spokesman, was robust in his response to Mr Tusk's suggestion there will be a "special place in hell" for those who promoted Brexit without any plan for how to safely deliver it.
East Antrim MP Mr Wilson accused the European Council president of showing "contempt" for Brexit voters.
"This devilish euro maniac is doing his best to keep the United Kingdom bound by the chains of EU bureaucracy and control," he said.
"It is Tusk and his arrogant EU negotiators who have fanned the flames of fear in an attempt to try and overturn the result of the referendum.
"All he will succeed in doing is stiffening the resistance of those who have exercised their choice to be clear of Tusk and his trident-wielding cabal."
His party leader Arlene Foster accused Mr Tusk of being "deliberately provocative" and "disrespectful".
"Clearly the pressure is beginning to mount in Brussels," she said.
"I think it was deliberately provocative I have to say, very disrespectful to those of us who voted to leave the European Union. He should reflect on what he had to say.
However, Sinn Fein President Mary Lou McDonald backed Mr Tusk's use of language.
"You are not going to convince me that anything Donald Tusk says could further harden the position of the Boris Johnsons' or the Rees-Moggs' of this world," she said.
"They are people who have acted with absolute contempt for this country, utter disregard for the experiences of Irish people north and south, with utter disregard for the peace process that has been collectively built over decades.
"Their position is the most hardline of hardline, it is their language that is intemperate and it is their position that is untenable."
Ulster Unionist leader Robin Swann called for cool heads all round, accusing both Mr Tusk and Mr Wilson of trading "harsh words".
"Leo Varadkar and Donald Tusk may find Mr Tusk's uncouth words amusing, but they are no laughing matter," he said.
"They may feel they are flexing some EU muscle, but the increasingly arrogant and confrontational approach they have adopted could ultimately lead to disaster socially and economically. It's time for cool heads instead of harsh words."