German Chancellor Angela Merkel has called for clear-headed negotiations with "close partner" Britain over its departure from the European Union, urging caution in the process.

Merkel issued the statement on Saturday, just hours after foreign ministers from the six founding members of the EU called for a quick exit from the 28-member bloc.

"The negotiations must take place in a businesslike, good climate," Merkel said after a meeting of her conservative party in Hermannswerder, outside Potsdam, to the west of the German capital Berlin.

"Britain will remain a close partner, with which we are linked economically," she said, adding that there was no hurry for the UK to invoke Article 50 of the Lisbon Treaty - the first step it must take to set in motion the exit process.

"It should not take ages, that is true, but I would not fight now for a short timeframe," Merkel said, in contrast with the more urgent call by the foreign ministers of Germany, France, Italy, the Netherlands, Belgium and Luxembourg, who were meeting to the north of the German capital.

In an interview with Al Jazeera, George Vella, foreign minister of Malta, agreed with Merkel's assessment, saying that the exit should be done in a "reasonable way", adding that negotiations should be studied carefully, "to achieve the maximum cooperation of the United Kingdom".

Merkel and French President Francois Hollande will meet Matteo Renzi, Italy's prime minister, in Berlin on Monday to discuss future steps.

'Painful process'

Following the foreign ministers' meeting earlier on Saturday, the officials issued a joint statement saying, "We now expect the UK government to provide clarity and give effect to this decision as soon as possible".

Jean-Marc Ayrault, France's foreign minister, said the pressure would be "very strong" on British Prime Minister David Cameron at an EU summit on Tuesday to speed up the process.

The outcome of Thursday's EU referendum - a 52-to-48 split in favour of Britain's exit - caused financial markets to fall sharply and brought the British pound down to a 31-year low, its biggest drop in history.

There are now fears that the vote could set off a chain reaction of further breakaway bids by other EU members battling hostility to Brussels.

There are also worries the outcome could lead to the break-up of the UK itself after Scotland raised the prospect of another independence vote..

Donald Tusk, the EU president, has warned of a "painful" process, saying "any delay would unnecessarily prolong uncertainty".

READ MORE: What will happen after Brexit?

US President Barack Obama, who publicly threw his weight behind British EU membership during a visit to London in April, insisted that the "special relationship" between the two countries was "enduring".

Following the UK's vote in favour of exiting the bloc, Dutch far-right MP Geert Wilders and French National Front leader Marine Le Pen called for referendums on EU membership in their own countries immediately.

The British vote will lead to at least two years of divorce proceedings with the EU, the first exit by any member state.

Cameron, who led the campaign to remain in Europe to defeat, after promising the referendum in 2013, said he would resign by October and it would be up to his successor to formally start the exit process.

Cameron's Conservative Party rival Boris Johnson, the former London mayor who became the most recognisable face of the Leave camp, is now widely tipped to seek his job.