Former German chancellor Helmut Kohl, the architect of German reunification and a leading driver of European integration, said the EU must allow Britain time to sort itself out after its referendum vote to leave the bloc.
Kohl, now 86 and in poor health, also told Germany's mass-selling daily Bild in its Thursday edition that the EU should show greater respect for national and regional identities in Europe and not impose too much standardization on member states.
Bild did not directly quote Kohl in its interview, which was headlined "Helmut Kohl - Europe needs to pause for breath", but paraphrased him as saying it would be "a giant mistake" to slam the doors on Britain.
"He pleaded for calm and warned against (acting towards Britain with) unnecessary toughness and haste.... The most important thing is for the country itself to decide what it wants," Bild quoted Kohl as saying.
Kohl, a Christian Democrat, served as chancellor from 1982 to 1998, working closely with France's socialist president Francois Mitterrand to push the EU towards monetary and economic integration, including the introduction of the euro currency.
He oversaw German reunification after the fall of the Berlin Wall in 1989 and was the mentor of Angela Merkel, who has led Germany since 2005 and is Europe's most powerful leader.
Merkel has also urged the EU to give Britain time to sort through its political mess before the start of formal talks on its exit and the terms of its future relationship with the bloc.
Kohl said Britain's vote for exit, or Brexit, was not a purely British phenomenon but reflected general "unease" among Europeans. The EU needs to take a step back before slowly taking two steps forward at a speed that is manageable for all member states, he added.
Kohl has been wheelchair-bound since suffering a fall in 2008. Last year he was hospitalized for several months after hip replacement surgery.