RIYADH, Oct 5 (Reuters) - Saudi Arabia has agreed to buy Russian S-400 air defence system, Saudi-owned al-Arabiya television reported on Thursday, on the sidelines of a visit by Saudi King Salman to Moscow.

The Dubai-based television channel also said that Saudi Arabia had signed a memorandum of understanding to help the kingdom in its efforts to develop its own military industries. (Reporting by Stephen Kalin, Writing by Sami Aboudi)