The EU has urged David Frost to end his “political posturing” over negotiations on the Northern Ireland protocol and accept that he cannot undo Brexit.

The European Commission vice-president Maroš Šefčovič was commenting after Lord Frost, the UK’s Brexit minister, called for an injection of “more urgency” into the talks aimed at solving the dispute over checks and controls on goods going from Great Britain to Northern Ireland.

The comments by Frost and Šefčovič on Sunday suggest the two sides are as far apart as ever, dashing hopes raised by the cabinet minister Michael Gove’s remarks that he was “confident” article 16, which would suspend some or all of the protocol, would not have to be triggered.

Šefčovič told BBC One’s The Andrew Marr Show he was surprised by Frost’s call for urgency because “sometimes I have the feeling that in our meetings I’m the only one who pushes for urgent solutions”.

He said the EU had offered a solution on 30 June to one of the main issues over medicine supplies but that the UK was still dragging its heels.

“I remember very well Lord Frost telling me that what is very important for him is not only content but also process and therefore I was waiting [to see] if we can deliver on that solution jointly. And I have to say that [as of] today this is not the case.

“I don’t think that it will solve the most pressing issue for the people of Northern Ireland and therefore we might be acting alone to make sure that the Northern Ireland people have the medicines they need,” he said.

On the removal of checks down the Irish Sea, Šefčovič reiterated that the EU had already made proposals to cut customs paperwork by half and eliminate 80% of the checks on food.

In an article in the Mail on Sunday, Frost said those “solutions don’t deal with the problems”, pointing out that 200 retailers had stopped delivering to Northern Ireland and Marks & Spencer had withdrawn its entire click and collect range for Christmas “because of the uncertainties in delivery timetables”.

“There’s a simple solution. Goods which both we and the EU agree aren’t going to leave Northern Ireland should not be treated as if they were moving from one country to another – because they are not,” he said. “But at the moment the EU says it is impossible. I urge them to think again.”

Pressed on this point, Šefčovič said it was impossible to remove all surveillance of goods as the EU needed an “overview” on movement of goods entering the single market. “We cannot undo the Brexit,” he said.

Frost’s comments on Sunday suggest the UK’s approach has not changed despite an apparent shift in tone two weeks ago and that triggering article 16 remains a possibility.

“The current problems with the protocol go to the heart of our territorial integrity, of what it means to be one country and one market. They will not just disappear,” said Frost. “I still hope the EU can show the ambition needed to fix the problem by agreement. If they can’t, of course we will have to safeguard our position in other ways.”