Italian Prime Minister Mario Monti flew unexpectedly to Brussels Thursday for what appeared to be a private visit ahead of a series of meetings with European leaders over the coming weeks.

There was no official word on what Monti was doing in Brussels, where he served for 10 years as a European Commissioner but Italian and European Union officials said they were aware of no scheduled meetings.

A European Commission spokesman said no meetings were scheduled with Commission President Jose Manuel Barroso or Monetary Affairs Commissioner Olli Rehn.

Monti is due to meet French President Nicolas Sarkozy on Friday during a one-day trip to Paris.

He will meet German Chancellor Angela Merkel and British Prime Minister David Cameron on separate visits to Berlin and London later in the month before a summit of European Union leaders in Brussels at the end of January.

Italy is still struggling to contain an escalating debt crisis which has sent its borrowing costs to untenable levels and threatened to spill over into a wider European crisis.

Thursday, the yield on its 10-year bonds stood at more than 7 percent, around the level which ultimately pushed Greece into seeking an international bailout.

(Reporting By Paolo Biondi and Luke Baker in Brussels)