March 19 (Reuters) - A landslide caused the Milan-San Remo race to be re-routed on Saturday, organisers said. The first of the five so-called monument races was diverted between Genova Voltri and Arenzano, taking the peloton on to the A10 autostrada and adding four kilometres to the original 291km distance. A top quality field began in Milan with the likes of Peter Sagan (Tinkoff), Swiss veteran Fabian Cancellara (Trek-Segafredo) and Alexander Kristoff (Katusha) among the favourites for the 107th edition of the race. (Reporting by Martyn Herman, editing by Ed Osmond) More...