RIYADH, May 13 (Reuters) - The United States and Saudi Arabia have discussed Riyadh's potential purchase of Lockheed's F-35 jets, two sources briefed on discussions told Reuters, referring to a military aircraft that the kingdom has reportedly been interested in for years.

However, it is not clear if Washington would permit the kingdom to move forward with a purchase that would give Saudi Arabia an advanced weapon used by close U.S. ally Israel, one of the sources said.

"(Qualitative Military Edge) with Israel has come up," the second source said, referring to U.S. guarantees that Israel receives more advanced American weapons than Arab states.

The sources spoke to Reuters on condition of anonymity.

Israel has owned F-35s for nine years, building multiple squadrons.

Governments in the Gulf have long sought the most advanced fighter jet, built with stealth technology allowing it to evade enemy detection. If the U.S. did approve the transfer, Saudi Arabia would be only the second Middle East state after Israel to operate F-35 fighters.

During Tuesday's visit by U.S. President Donald Trump to Riyadh, the U.S. is poised to offer the kingdom an arms package worth well over $100 billion, six sources with direct knowledge of the issue told Reuters previously.

(Reporting by Pesha Magid in Riyadh and Mike Stone in Washington. Editing by Mark Potter)

((andrew.mills@thomsonreuters.com +97455075787))