European Commission President Jean-Claude Juncker will ask British Prime Minister David Cameron to move as soon as possible to clarify what course his country is taking following last week's referendum to leave the EU, he says.
"I would like the United Kingdom to clarify its position, not today, not tomorrow at 9 am, but quickly. We cannot find ourselves in a period of prolonged uncertainty," Juncker told an emergency plenary session of the European Parliament.
"I don't want the idea to take hold that there could be secret negotiations in dark rooms, with curtains drawn, between representatives of the United Kingdom and national governments, commissioners and director generals," he added.
Juncker also said he has issued a presidential order banning all EU commissioners from discussing Brexit with British government officials for the time being.