Johnson said the E.U. was refusing to give Britain a trade deal like the one it has with Canada, which the U.K. is seeking.
Refusing to bow to U.K. pressure, E.U. Commission chief Ursula von der Leyen said less than an hour after Johnson made his ultimatum, that the E.U. still wants a Brexit trade deal "but not at any price."
The U.K. has threatened to walk away from the talks if a deal is not struck by the E.U. summit that ends later on Friday.
Johnson didn't go that far, but said the E.U. seemed to have "abandoned" the idea of a deal. Adding that Britain would listen if there was "a fundamental change of approach" from Brussels.
Britain officially left the E.U. on Jan. 31 but remains part of its economic structures until Dec. 31. After that, it needs a new trade agreement or will face tariffs and other economic barriers with the E.U. — its biggest trading partner.
However, a trade agreement remains elusive and E.U. leaders said in a joint statement that it was now up to the U.K. "to make the necessary moves to make an agreement possible."
Meanwhile, Britain's foreign minister Dominic Raab said on Friday Britain was disappointed by the bloc's tone. Adding that there were only narrow differences remaining in trade talks between the U.K. and the E.U., insisting the bloc must show more "flexibility" to get a deal over the line.
Raab told the BBC differences remained on only two issues: EU boats' access to U.K. fishing waters, and "level playing field" rules to ensure fair economic competition between Britain and the bloc.
Download the NBC News app for breaking news and politics
But months of talks have seemingly ground to a halt.
German Chancellor Angela Merkel, the veteran diplomat, sought to soothe tempers on Friday, saying that "we asked Britain to be willing to compromise. This of course means that we too have to make compromises."
While chief E.U. negotiator Michel Barnier signaled he expected the talks to continue.
"The negotiations aren't over," he said, adding that his team would be London-bound for more talks next week and planned to host negotiations in Brussels the week after that. Britain has not publicly agreed to that timetable.
Trust between the two sides, already frayed by years of Brexit acrimony, took a further nosedive last month when Johnson introduced legislation that could breach parts of the withdrawal agreement he himself signed with the E.U. only last year. His move sparked resignations in protest.