Hundreds of truck drivers blocked roads across Bulgaria on Thursday as European Union leaders met in Sofia, protesting proposed EU rules they say would cost their jobs and put their firms out of business.

Transport company owners described the initiative, known as the Mobility Package, as a protectionist measure designed to help rival firms in western Europe. The Bulgarian transport association said around 120,000 drivers from the country would lose their jobs under the proposed rule changes.

Trucks from Bulgaria and other low-wage eastern European countries are a common sight on the roads of western Europe, competing with local firms whose drivers are much higher paid.

Under the package, backed by France, Germany and other higher-wage states, truck drivers from eastern Europe would receive the same payment for work abroad as those employed by western European transport companies.

The package has long been the subject of negotiations between EU member states and has yet to be laid before the European Parliament.

The Bulgarian government backed the local truck companies.

“We declare our strong support for Bulgarian carriers,” Transport Minister Ivaylo Moskovski said.

Prime Minister Boyko Borissov, who is hosting the EU summit, said the proposed changes would “kill the Bulgarian sector.”

French President Emmanuel Macron said he hoped a compromise could be found in the coming months. “We will find a balanced deal together that will ensure the proper working of the single market, good social protection and fair competition in the transport sector. September has to be our objective,” he told a news conference at the Sofia summit.

Drivers from Bulgaria, where average monthly wages of little more than 500 euros ($600) are among the lowest in the EU, often spend weeks moving loads between countries including Germany, France and Britain before returning to their home base.

Under the package, drivers would have to rest for at least 45 hours in a hotel rather than their cab and return home every three weeks.

Bulgarian transport firms said this would nullify eastern European companies’ competitive advantage.

“These restrictions are absolutely unnecessary,” said Vladislav Kalchev, owner of a transport company. “They are trying to help, in some way, the market in the big countries.”