The European Commission will consider a legal challenge against Germany over planned road tolls that appear to violate European Union anti-discrimination laws by targeting foreign motorists, the Commission's President said.
In an interview in Sueddeutsche Zeitung, Jean-Claude Juncker said the toll -- which Chancellor Angela Merkel's government passed with doubts itself in March -- does not appear to conform with EU rules prohibiting discrimination against foreigners.
"We have considerable doubts that the law succeeds (in preventing discrimination against foreigners)", Juncker told the German daily.
"The Commission, as the guardian of the EU treaties, now has to explore whether the treaties have been violated -- if necessary at the European Court of Justice."
The toll, which Germany's parliament approved in March, will force foreign car drivers to pay up to 130 euros ($143) a year to use the country's motorways.
German drivers would also pay the toll but would receive a corresponding reduction in automobile taxes, which critics inside and outside the ruling grand coalition say contravenes EU rules.
Juncker's comments followed a report in Die Welt newspaper that quoted Commission sources saying it planned to launch a legal challenge against Germany.
German Transport Minister Alexander Dobrindt rejected the criticism from Juncker. "If there are comments from Brussels, the Commission should tell us in detail what they don't like out the law," he said in a statement in Berlin.
The toll is a pet project of Dobrindt and his Bavarian Christian Social Union (CSU) party.
The CSU's bigger sister party, Merkel's Christian Democrat (CDU), as well as the junior centre-left coalition partner, the Social Democrats (SPD), were long openly sceptical.
The SPD rejected the toll in the 2013 election campaign, for the same reasons Juncker cited.
In February a report by EU experts cast doubt on the toll as discriminatory.
Dobrindt argued that the new motorway toll will generate some 500 million euros for the state each year, which would be invested in transport infrastructure.
German President Joachim Gauck has not yet signed the law, which is normally a formality, according to a report in Bild newspaper. The daily said he has spent three weeks studying whether the law conforms with Germany's constitution.