A Saudi Arabian court began the trial of two Jordanians accused of spying against the kingdom for Israel's Mossad intelligence agency, Saudi-owned al-Arabiya said on Monday.
The charges under consideration by the Specialized Criminal Court include plotting a terrorist act during the annual Muslim haj pilgrimage four years ago and supporting Islamic State militants, Al-Arabiya wrote on its website.
It did not provide further details about the case.
Saudi Arabia, the birthplace of Islam and site of its holiest shrines, does not officially recognise Israel. It has maintained for years that normalising relations hinges on an Israeli withdrawal from Arab lands captured in the 1967 Middle East war - territory Palestinians seek for a future state.
However, increased tensions between Riyadh and Tehran have fuelled speculation that shared interests may push Saudi Arabia and Israel to work together against what they regard as a common Iranian threat.
In a sign of an apparent thaw between the two countries, Saudi Crown Prince Mohammed bin Salman said in April that Israelis were entitled to live peacefully on their own land.
Last month, Saudi Arabia opened its air space for the first time to a commercial flight to Israel, a move hailed by an Israeli official as historic following two years of efforts.