Italy’s relations with the US took a further blow yesterday when Silvio Berlusconi’s conservative government said it was summoning the American ambassador in Rome to explain the disappearance of a radical Muslim cleric, who was snatched from a Milan street two years ago. Hassan Mustafa Osama Nasr, also known as Abu Omar, was sent via two American military bases to his native Egypt for imprisonment and interrogation. Mr Nasr was subsequently released temporarily. In telephone calls intercepted by the Italian police, the cleric said he had almost died under torture.