ZURICH/MILAN (Reuters) - Rail traffic through the Alps between Switzerland and Italy was halted on Wednesday after an anonymous caller said there was a bomb on a freight train, Swiss police said.

The Simplon tunnel was closed at around 11:30 a.m. (7.30 am. ET) as police dog handlers searched for explosives. The police said the tunnel might reopen on Wednesday evening.

A spokesman for Swiss Rail said buses were taking passengers to the Italian border city of Domodossola.

(Reporting By Martin de Sa'Pinto and Danilo Masoni; Editing by Robin Pomeroy)