(Adds Egyptian security source, paragraph 6)

CAIRO, Feb 3 (Reuters) - An Italian student from Britain's Cambridge University who went missing last week in Cairo is likely dead, the Italian foreign ministry said on Wednesday.

It said that it was still waiting for official confirmation from Egyptian authorities about the fate of Giulio Regeni, 28, who disappeared on Jan. 25, the five-year anniversary of the 2011 uprising that ended Hosni Mubarak's 30-year rule.

Tensions were high in Egypt in the run-up to the anniversary, with police detaining activists and warning people not to demonstrate. No significant protests took place.

"The Italian government had learnt of the probable tragic end to this affair," the foreign ministry said in a statement issued in Rome.

Foreign Minister Paolo Gentiloni had expressed his deep condolences to Regeni's family, the statement said.

An Egyptian security source said the interior ministry would not comment on the case until the conclusion of its investigation.

The Italian foreign ministry did not give any indication of how the student might have died or whether his body had been found. Italian news agency Ansa said his body had been found in a ditch in a Cairo suburb but gave no further information.

A friend of Regeni said he disappeared after leaving his home in an upper middle class area to meet a friend downtown.

Last year, Islamic State militants kidnapped a Croatian man from the outskirts of Cairo and later beheaded him, but such incidents are rare and there was heavy police presence in downtown Cairo when Regeni went missing.

(Reporting by Ahmed Aboulenein; Additional reporting by Antonella Cinelli and Crispian Balmer in Rome; editing by Grant McCool) ((ahmed.aboulenein@thomsonreuters.com; +20 2 2394 8097; Reuters Messaging: ahmed.aboulenein.thomsonreuters.com@reuters.net))

Keywords: EGYPT ITALIAN/