BRUSSELS — A top European Union official said today that trade talks with the United Kingdom still face “substantial work” that might spill over into next week, with a perilous deadline drawing ever closer.

Valdis Dombrovskis, the EU’s top trade official, said “there are still important elements to be resolved. So there is still substantial work to do,” if a full agreement is to come into force on Jan. 1.

Several deadlines have already passed and Dombrovskis said the talks could go on for many days more. His comments dampened hopes that a deal could be approved when the EU leaders meet in a video conference on Thursday.

“We actually have seen many deadlines to come and go. But there is one deadline which will not be able to move, which is January 1st, the next year when the transition period ends,” Dombrovskis said. That does not mean there are still six more weeks to negotiate since the EU approval process would need to take around four weeks.

The U.K. left the EU on Jan. 31, but a transition period when EU rules apply to trade and other issues runs until the end of next month. Both sides had hoped to get a trade deal by then to save hundreds of thousands of jobs that could be at stake if Brexit amounts to a brutal cliff edge divorce.

But talks have proven exceptionally difficult, with the two sides refusing to budge on three key issues – fisheries, how to check compliance of the deal and standards the U.K. must meet to export into the EU.

The bloc accuses Britain of wanting to retain access to the EU’s lucrative markets, much like any EU country, without agreeing to follow its rules. The EU fears Britain will slash social and environmental standards, and pump state money into U.K. industries, becoming a low-regulation economic rival on the bloc’s doorstep.

Britain says the EU is making unreasonable demands and is failing to treat it as an independent, sovereign state.

If there is no deal, businesses on both sides of the English Channel will face tariffs and other barriers to trade starting on Jan. 1. That would hurt economies on both sides, with the impact falling most heavily on the U.K., whose economy is already reeling under the coronavirus pandemic.