BRUSSELS — The outlook for a vast free trade pact between the European Union and the United States was bleak Friday, with EU ministers discussing whether to change their approach after conceding that a deal cannot be sealed before President Barack Obama leaves office.

After three years of negotiations, big differences remain over the Trans-Atlantic Trade and Investment Partnership, which is meant to lift trade barriers between the world’s biggest commercial partners, spark sorely-needed economic growth and create new jobs.

“Completion of the negotiations with the U.S. by the end of this year is not realistic. So it is not realistic to reach final agreement by the end of President Obama’s administration,” Slovak Economy Minister Peter Ziga, whose country holds the EU’s rotating presidency, told reporters after informal trade talks in Bratislava.

“We’ve had negotiations for three years and no chapter out of 30 chapters has been closed,” Ziga said. “It will take a lot of time to get there.”

TTIP, as the potential deal is known, is aimed at removing barriers to trade between the EU and the U.S. to boost economic growth and employment. The European Commission estimates that the pact could boost EU economic output by 119 billion euros ($133 billion) a year and that of the U.S. economy by 95 billion euros ($106 billion).

Thousands of people have demonstrated against the pact in Germany and Belgium over the last week. They fear the agreement is a threat to the environment and public health, and would give more power to big multinational companies.

Still, European officials were keen to seal a deal on TTIP before Obama leaves office in January. Looming elections in France and Germany are also weighing on the negotiations.

A new round of talks is scheduled for early October, but few hold hopes for a breakthrough.

“I don’t necessarily see it as the last one but let’s see how far we get,” EU Trade Commissioner Cecilia Malmstroem said.

Given the public opposition and slow pace of progress, some think now is a good time to pause and consider a fresh approach once it’s clear who will hold office in the White House from next year.

“It would be reasonable, given that the subject has such a negative connotation now, to completely relaunch with a new name after the U.S. elections, with more transparency and clearer objectives, “said Austrian Economy Minister Reinhold Mitterlehner.

In contrast, good progress has been made on the trade deal with Canada, known as CETA. Malmstroem’s office will draw up a joint declaration to annex to the agreement to explain some elements, like public services as well as investment protection and arbitration. The plan is to sign the agreement at the EU-Canada summit in Brussels on Oct. 27-28.

“The Americans have not been willing to make offers the way Canada has so it’s guaranteed there will be no agreement this year,” said German Economy Minister and Vice Chancellor Sigmar Gabriel.

“If we do restart the negotiations, we’ll have to see who the next American president is,” he said.

On the other side of the Atlantic, U.S. analysts see little chance of a U.S.-European deal anytime soon.

“Very unlikely,” Caroline Freund, senior fellow at the Peterson Institute for International Economics, said. “Europe is struggling with Brexit and migration, and the TTIP is hugely unpopular in Germany.”

There’s a prevailing view that an agreement would be more likely under a President Hillary Clinton than a President Donald Trump.

“Even if a President Trump wanted a TTIP, it would be hard to get Europe to work with his administration,” Freund said, noting Trump’s comments that Britain would be ‘better off without’ the EU.

Paul Wiseman in Washington contributed to this report.