As Iran and the P5+1 group of world powers prepare for the final negotiations on reaching an agreement on Tehrans nuclear programme, the Saudi leadership will have strong concerns over the outcome.
Iran is Saudi Arabias main rival in the region and Riyadh would not be quick to welcome an agreement that would enable the Islamic Republic to increase its political influence in the Middle East.
The kingdom officially welcomed the signing of the preliminary nuclear framework at the start of April. King Salman bin Abdulaziz al-Saud telephoned US President Barack Obama to say he hoped a final settlement of the nuclear dispute would strengthen the stability and security of the region and the world.
However, the already-fractured relationship between the two countries has further deteriorated in recent months, with Saudi Arabia accusing Iran of providing support for the Houthi rebels in Yemen.
Tehran and Riyadh have also found themselves backing opposing sides in the Syrian civil war, with Iran continuing to support embattled President Bashar al-Assad against Sunni rebel groups.
Saudi leaders fear that a positive outcome for the Iran nuclear talks set for a deadline of 30 June could boost the Islamic Republics economic and military power in the region.
A sanctions-free Iranian economy has the potential to become the largest in the region and could allow Tehran to increase support for its political allies in the Middle East, as well as draw investment away from Saudi Arabia.
If Iran is relieved of sanctions, it could also boost oil exports significantly in the short term and begin to expand oil and gas production capacity in the long term. This would not only negatively affect oil prices, it would also increase Tehrans influence within Opec and may require other members of the oil-exporting group to cut production to make room for a resurgent Iran.
Above all, Riyadh fears that a soft nuclear agreement would allow Tehran a path to develop a nuclear bomb. Suspicions of Iran rushing to weaponise its uranium enrichment programme could lead to a nuclear arms race in the region, with Saudi Arabia the next country in line to develop the weapons.
Whatever the Iranians have, we will have, too, Prince Turki bin Faisal, the former Saudi intelligence chief, said at a recent conference in South Korea.
It is widely thought that Pakistan would be able to provide Saudi Arabia with the technology to produce nuclear weapons within a relatively short space of time.
The terms of the comprehensive agreement targeted by Iran and world powers have not yet been confirmed. The US will have its work cut out to convince its allies in Riyadh that Iran has not been given an easy ride.