LONDON, 16 (UPI) -- Israeli jets entered Syria earlier this month to destroy a shipment of nuclear material supplied by North Korea, Western intelligence sources said.

The Sept. 6 air raid about 50 miles from the Iraqi border reportedly destroyed a cache of nuclear material that had arrived days earlier by ship from North Korea marked as a cargo of cement, The Times of London reported Sunday.

Preparations for the raid began in late spring when Israeli intelligence received information Syria was trying to buy a nuclear device from North Korea, The Times reported.

No news of the raid emerged until Syria complained Israeli jets had violated its airspace, dropping fuel tanks to lighten their load as Syrian air defense chased them back across the border.

Syrian leaders have revealed no further details, except to say they are considering "responses" to the air invasion.

Israel's government declined to comment on the raid beyond saying Israeli soldiers demonstrated unusual courage in acting against Syria, The Times reported.