British negotiators need to better articulate their position on Britain’s departure from the European Union, a German industry leader stressed Friday, echoing the frustrations of EU Brexit negotiators.

Dieter Kempf, president of the Federation of German Industries (BDI), said that he was still concerned by Brexit, citing the U.K. as Germany’s most important trading partner in Europe.

“Of course we are concerned because the U.K. is one of our most important trade partners – or the most important trade partner in Europe for the German industry,” he told CNBC Friday.

Kempf said that he would rather see a solution whereby Britain either remained a full member or a close partner of the EU.

“In our eyes we would better see an EU without a Brexit or let’s say an EU with the U.K. as a strong partner. However the population in Great Britain has decided, so we have to deal with that.”

He added: “We are now asking for strict and very serious negotiations about the details of the Brexit which we have not yet really seen from the British side.”

Various EU officials have said that the pace of Brexit negotiations needs to pick up.

Guy Verhofstadt, who represents the European Parliament in the Brexit process, told CNBC last month that he was “pessimistic” about discussions between negotiators.

Verhofstadt told CNBC that British negotiators need to agree on a methodology to work out outstanding financial commitments the U.K. owes to the EU before discussing a future relationship between the two.

“It’s like in a divorce and in a divorce when you go away you don’t let all the bills with the rest of the family,” he said.