European Union top economic official said that the EU is ready to help Greece in consolidation and reform programs to head off concerns triggered by the sovereign credit rating decline by rating agency Fitch.

"We take note of the fact that the sustainability of public finances in Greece draws the attention of financial markets and rating agencies," Economic and Monetary Affairs Commissioner Joaquin Almunia said in a statement.

He said that the European Commission, the EU's executive arm, "stands ready to assist the Greek government in setting out the comprehensive consolidation and reform program, in the framework of the treaty provisions for euro-area member states."

"A difficult situation in one euro-area member state is a matter of common concern for the euro area as a whole," he said, adding that the commission "will continue to monitor the situation in Greece very closely, in close contact with the president of the Eurogroup."

But the EU economic chief did not mention what kind of assistance the bloc would offer Greece.

Almunia urged the Greek authorities to put in place more measures to deal with the "very substantial economic and fiscal challenges," despite the "important step in the right direction" by adopting the draft budget on Nov. 20.

Greek stocks and bonds tumbled Wednesday after Fitch Ratings cut its rating on government debt to BBB+ and two other major ratings companies are threatening to do the same.

The benchmark Athens Stock Exchange General Index fell by 6.1 percent, its biggest intraday decline since Nov. 26.

The spread between the Greek and German 10-year benchmark bonds widened to 221 basis points from 130 basis points on Oct. 5.

Greece, the lowest-rated country in the euro zone, is struggling to cut a budget deficit of 12.7 percent of gross domestic product, well above the three-percent ceiling set for euro zone nations.