"I do think one can legitimately and seriously question the timing of it, whether the timing is appropriate," Simon O'Connor, the commission's economic affairs spokesman, told a news conference.

He noted that the downgrade coincided with an "important bond sale that Italy was undertaking today."

The spokesman said the government of Italian Prime Minister Mario Monti had taken "determined and wide ranging" policy actions to clean up its public finances and repair structural weaknesses.

"We consider that Italy's reform effort in the past year has been impressive and it may not be an exaggeration to say it has been unprecedented," O'Connor said.

Moody's cut Italy's rating overnight by two notches, citing the knock-on effects of a possible Greek exit from the eurozone and Spain's banking woes.

Despite the setback, Italy pulled off a successful bond auction, raising 3.5 billion euros ($4.3 billion) in three-year bonds at a rate of 4.65 percent, down from 5.30 percent last month, although a longer-dated bond rose.