"I have a problem here because, to be frank, I have no new information to offer to you," the senior European official told a briefing for reporters ahead of the two-day European Council which will consider any request.
"We have not received a letter from Prime Minister May. We have not received the request from the UK on the extension of Article 50 in any other form," he said, despite reports that May plans to ask her colleagues for more time.
"For the moment, there is no request from the UK. Maybe it will come, maybe it won't come," he said, as May mulled whether to request a short extension to pass Brexit legislation or a long one to rethink Britain's strategy.
Without an extension, Britain will fall out of the European Union in nine days.
"What I can say now? ... I have no basis to speculate about length," the official said.
"I guess the 27 will have a debate on Brexit in light of the state of play of situation."
"PM won't be asking for a long extension," it quoted a Downing Street official as saying on the eve of a summit with EU leaders in Brussels.
"There is a case for giving parliament a bit more time to agree a way forward, but the people of this country have been waiting nearly three years now.
"They are fed up with parliament's failure to take a decision and the PM shares their frustration."
Exasperated European leaders are demanding London to tell them clearly what it wants, warning that the risk still remains that Britain could crash out of the bloc on March 29, ending its 46-year membership without formal arrangements.
The British premier is struggling to keep control of the Brexit process after MPs last week decisively rejected the EU divorce deal for a second time.
She has reluctantly accepted that Brexit must be postponed, amid fears of an economic shock if Britain ends its membership of the EU with no new arrangements in place.