BRUSSELS: European Parliament leaders urged the EU on Tuesday to probe new amendments to Hungary's constitution that are viewed by many critics as undermining democracy and the rule of law.

The EU and the U.S. are concerned that the changes passed Monday enshrining policies previously struck down by the country's highest court put too much unchecked power in government hands.

Hungarian Prime Minister Viktor Orban's "government doesn't want to apply European principles and values," warned Guy Verhofstadt, head of the Liberal parties' caucus.

The 27-nation bloc must therefore launch a formal investigation and possibly sanction the country to bring it back in line, he added.

The bloc's executive arm, the European Commission, and its human rights watchdog, the Council of Europe, should both examine the legal changes and suggest modifications if necessary, said Joseph Daul, leader of Parliament's center-right majority caucus.

Among the government policies struck down by the Constitutional Court over the past months and now added to Hungary's Fundamental Law are the possibility for local authorities to fine or jail homeless people living in public areas, a ban on political campaign ads on commercial radio and TV, and a contract obliging university students who accept state scholarships to work in Hungary for years after graduation.

EU Commission spokesman Olivier Bailly said the laws will be checked as soon as possible to make sure they "are in line with EU laws and EU values."

"If necessary we will use our legal instruments to make sure that these laws are changed," he added.

The European Union is able to fine companies like Microsoft Corp. if they are caught breaching its antitrust rules, but the bloc lacks teeth if one of its member states changes its laws to curb the rule of law or democracy itself.

Existing procedures have proven insufficient, unpractical, too slow or all three. Four nations led by Germany this month urged the creation of a new powerful watchdog to monitor legal compliance with the EU's fundamental values across the bloc.

In Berlin, the German Foreign Ministry said Minister Guido Westerwelle held an "open and in part highly controversial" discussion over the constitutional changes with visiting Hungarian President Janos Ader.

The ministry statement did not spell out details of the German position on the amendment, but the unusually harsh description made clear European heavyweight Germany is deeply concerned about the legal changes in the former Communist country.