CAIRO (Reuters) - President Mahmoud Ahmadinejad arrived in Cairo on Tuesday for the first trip by an Iranian head of state to Egypt since the 1979 revolution, underlining the more open ties that have developed since Egyptians elected an Islamist head of state.

President Mohamed Mursi kissed Ahmadinejad as he disembarked from his plane at Cairo airport, footage broadcast by Egyptian state television showed.

Such a visit would have been unthinkable during the rule of Hosni Mubarak, the military-backed autocrat whose 30 years in power safeguarded Egypt's peace treaty with Israel and resulted in deeper ties between Cairo and the West.

(Writing by Tom Perry; Editing by Janet Lawrence)