By Ahmed Saeed

KARBALA, Iraq, June 25 (Reuters) - Carrying photos of loved ones killed in the war with the U.S. and Israel, Iranian pilgrims crossed into the Iraqi holy city of Karbala to commemorate Ashura, the holiest day on the Shi'ite Muslim calendar.

Ashura falls on the 10th day of Muharram, the first month of the Islamic calendar, and marks the anniversary of the death of Imam Hussein, a grandson of the Prophet Mohammad, who was killed in battle in 680 in Karbala.