Germany's foreign minister is urging the EU to adopt even tougher sanctions on Iran to hinder the country from building nuclear weapons.

Guido Westerwelle said Sunday "we must increase the pressure through sanctions" because Iran has failed to make any concessions during talks on its nuclear program over the past months.

His comments came a day before a meeting of European foreign ministers in Luxembourg at which further sanctions will be discussed.

They were the clearest indication yet that Germany is seeking tougher measures, though he stressed that the group of nations negotiating with Iran — the five permanent members of the United Nations Security Council plus Germany — remains committed to a political solution.

The U.S. and its allies accuse Iran of covertly developing nuclear weapons. Tehran denies that.