GOTEBORG, Sweden -- European Union leaders warned Britain Friday that it must do much more to convince them that Brexit talks should be broadened to cover future relations and trade from December.

At an EU summit in Sweden, Prime Minister Theresa May's government was urged to clarify how much Britain will pay in settlement of its financial accounts with the bloc and to ensure that there is no hard border created between Ireland and Northern Ireland.

Britain is due to leave the EU on March 29, 2019, but it must complete the complex and unprecedented departure process by next October so that parliaments can ratify any agreement.

May desperately wants to discuss future relations and trade, and EU leaders have suggested they could be ready to expand the talks next month if "sufficient progress" is made on the divorce bill, the status of Irish borders and the rights of citizens hit by Brexit.

"Great Britain need to clarify what they mean with the financial responsibility," the summit host, Swedish Prime Minister Stefan Lofven, told reporters in the city of Goteborg.

"We all hope that we can decide on the next phase but we still have some way to go," he said.

Britain has suggested that it might be willing to pay 20 billion euros ($23 billion) to fulfil its financial commitments, while EU officials have said the figure would more likely be between 60 and 100 billion euros ($71-118 billion).

Irish Prime Minister Leo Varadkar said there is no chance of progress unless he gets clear guarantees that Brexit will not result in any new barriers between his country and Northern Ireland, which is part of the U.K.

"We've been given assurances . that there will be no hard border in Ireland, that there won't be any physical infrastructure, that we won't go back to the borders of the past," Varadkar said. "We want that written down in practical terms in the conclusions of phase one."

"It's 18 months since the (Brexit) referendum. It's 10 years since people who wanted a referendum started agitating for one. Sometimes it doesn't seem like they've thought all this through," he said, of May's government.

The British government insists that the preliminary issues and future relations are inextricably linked and should be discussed together, and May remained hopeful that she will get the green light from EU leaders at their next summit in Brussels on Dec 14-15.

"Of course we want to move forward together, talking about the trade issues and trade partnership for the future," she said.

"I look forward to the European Union responding positively to that so we can move forward together and ensure that we can get the best possible arrangements for the future."

This EU summit in Sweden is ostensibly about employment and social welfare, but May has been using her visit to hold bilateral talks on Brexit with several leaders, including Lofven, Varadkar and EU Council President Donald Tusk.

Brexit negotiations are bogged down over preliminary issues, and the EU's chief Brexit negotiator has warned that progress must be made within the next week, by Nov. 24, to have any hope of broadening the talks this year.

"The clock is ticking," European Commission President Jean-Claude Juncker said Friday. "I hope that we will be able to come to an agreement as far as the divorce is concerned in the December (EU) council but work has still to be done."