BRUSSELS -- Fearing final rejection by a small Belgian region, leaders of the European Union warned early Friday that if a free trade deal with a close partner like Canada fails it could mean the end of such agreements with any other country.

The 28 EU member countries and Canada continued to push hard Friday to persuade Belgium's francophone Wallonia region to back the so-called CETA deal, which needs unanimity among all EU members. Belgium, in turn, can only back the deal if it has unanimity among all of its regions.

Wallonia piled on more pressure late Thursday by dismissing the EU's latest offer, which included concessions on anything from social security to data protection.

"At this stage, the document is still insufficient," Wallonia President Paul Magnette told reporters in the regional capital Namur.

EU Commission President Jean-Claude Juncker said he had invited Canada's International Trade Minister Chrystia Freeland to join in the talks with the EU and Belgium to make Magnette change his mind on Friday.

"We need this trade arrangement with Canada," said Juncker. "It is the best one we ever concluded and if we will be unable to conclude a trade arrangement with Canada, I don't see how it would be possible to have trade agreements with other parts of this world."

On Thursday, EU President Donald Tusk said that barring success "I am afraid, that CETA could be our last free trade agreement."

To have the deal between more than 500 million EU citizens and 35 million Canadians fall apart over the objections of a region of 3.5 million after seven years of talks would undermine the credibility of the EU as a whole, said Tusk.

Many others at the meeting joined in the astonishment that Wallonia could sway such clout in the face of nations like Germany and France.

"Nobody would understand if it were not possible now, after so many efforts," an exasperated Martin Schulz, the EU Parliament chief, told the summit leaders.

Even Belgian Prime Minister Charles Michel would like to do nothing better than sign on instead of dragging the summit of leaders into the byzantine subtleties of Belgium's constitutional setup between its Dutch, French, and German-speaking language groups.

Michel said he needed Wallonia's backing. "I have a lot of respect for the role of our parliaments and democracy. But democracy means that at one moment you need a decision."

The official signing ceremony of the deal is set for next Thursday when Canadian Prime Minister Justin Trudeau is supposed to attend an EU-Canada summit. Without the deal ready for signature, it will be cancelled.

Wallonia wants more guarantees to protect its farmers and Europe's high labour, environmental and consumer standards. It also fears the agreement will allow huge multinationals -- first from Canada, later from the United States, if a similar deal with Washington follows -- that would crush small Walloon enterprises and their way of life.

Proponents say the deal would yield billions in added trade through tariff cuts and other measures to lower barriers to commerce. At the same time, the EU says it will keep in place the region's strong safeguards on social, environmental and labour issues.

German Chancellor Angela Merkel insisted EU trade policy had not fallen off a cliff yet.

"I tell you: You can continue to trust Europe as a trading partner," she said.