Saudi Arabia is reported to have improved its ballistic missile capability by buying technology from China.
A US media report cites three unnamed sources for the previously unreported classified intelligence. It describes a suspected missile factory west of the capital Riyadh.
President Donald Trump is accused of not disclosing the intelligence to Congress which is infuriating Democrats.
As Trump refuses to rule out military action against Iran, the Saudi missile report heightens concerns of a Middle East arms race.
Al Jazeera's Adrian Brown reports from Beijing.