Wed Jul 23, 2008 11:32am EDT

By Dan Williams

TEL AVIV, July 23 (Reuters) - Iran is set to receive an advanced Russian-made anti-aircraft system by year-end that could help fend off any pre-emptive strikes against its nuclear facilities, senior Israeli defence sources said on Wednesday.

First delivery of the S-300 missile batteries was expected as soon as early September, one source said, though it could take six to 12 months for them to be deployed and operable -- a possible reprieve for Israeli and American military planners.