BRUSSELS (AP) -- Britain's European Union partners on Monday ratcheted up political pressure on Prime Minister Theresa May amid signs that some progress is being made in Brexit negotiations.
Britain leaves the EU on March 29 — the first country ever to do so — but a deal must be sealed in the coming weeks to leave enough time for the U.K. Parliament and European Parliament to sign off.
At a meeting of EU affairs ministers in Brussels on Monday, the bloc's Brexit negotiator, Michel Barnier, "explained that intense negotiating efforts continue, but an agreement has not been reached yet."
"Some key issues remain under discussion," he told them, according to a statement from EU headquarters.
The main obstacle to an agreement is how to keep goods flowing smoothly across the border between EU country Ireland and Northern Ireland in the U.K.
All parties have committed to avoid a "hard border" with costly and time-consuming checks that would hamper business. Any new customs posts on the border could also re-ignite lingering sectarian tensions.
"The ball is in the British court. It is a question of a British political decision," France's EU affairs minister, Nathalie Loiseau, told reporters at EU headquarters.
Belgian Foreign Minister Didier Reynders agreed, saying that the EU is "waiting for new news from London."
"We have time but not so much," he added.
The EU is awaiting Barnier's signal as to whether sufficient progress has been made to call an EU summit to seal a deal.
Signs have emerged in recent days that some progress is being made behind the scenes.
Austrian EU affairs minister, Gernot Bluemel — whose country holds the EU's rotating presidency until the end of the year — said "there is a certain dynamic in the negotiations, but it is too early to say how we are going to proceed on that."
On Thursday, Finnish Prime Minister Juha Sipila said that major progress was likely "within a week," based on his Brexit discussions with several EU leaders who visited Helsinki.
"We're going through crucial days now. We're very close now," Sipila said.
Germany's EU affairs minister, Michael Roth, underlined Monday that "the clock is ticking."
"The room for maneuver is very much limited and our British friends know exactly where our discussions are," he said.
Domestic pressure has also increased on May, after a transport minister in her government resigned last week.
Jo Johnson, younger brother of former Foreign Secretary Boris Johnson, backed calls for a second referendum on whether the country should leave the EU.
His call to test voter sentiment further complicates matters for May as she tries to strike a deal with EU leaders that would pass muster with her own cabinet and win backing in Parliament.
She has consistently rejected the idea of another nationwide vote on Brexit.
Pro-Brexit and pro-EU politicians alike are warning that the deal she seeks is likely to be shot down by Parliament.
Boris Johnson, a staunch Brexiteer, wrote in a column for Monday's Daily Telegraph that May's plan to adhere closely to EU regulations in return for a trade deal and an open Irish border amounts to "total surrender" to the bloc.
The proposed terms are scarcely more popular with advocates of continued EU membership.
Former Education Secretary Justine Greening on Monday called May's proposals the "worst of all worlds," and said the public should be allowed to vote again.
"We should be planning as to how we can put this final say on Brexit in the hands of the British people," Greening told the BBC.