The U.S. and its main European allies were caught unprepared in March after China brokered a deal between regional foes Saudi Arabia and Iran to revive diplomatic relations, after years of bitter rivalry that has fuelled conflict across the Middle East.

The Kingdom is also pressing ahead with efforts to thaw bilateral ties with Syrian President Bashar al-Assad, joining several other Arab states in moving to formally end Syria's regional isolation despite Western concerns.

"A reconfiguration is under way," said a French diplomatic source who was officially briefing reporters but required anonymity as is standard policy.

The ministers of the G7 – France, Britain, Germany, Italy, Canada, the U.S. and Japan, meet in Japan between April 16 to 18.

"The region is going through serious upheaval, be it the Iranian nuclear crisis aspect, but also the recomposition of the geopolitical balances with the Iran, Saudi, China deal. We can see something is happening with Syria after the earthquake," he said.

Certain Middle East allies, notably Saudi Arabia, have questioned U.S. security commitments to the region and have opted to remain neutral over Russia's war against Ukraine, pushing them to diversify their relationships, including with China, instead of relying on the West.

"The G7 must be able to preserve its security interests, which incidentally are also in the interest of regional security, but also global security," the diplomat said.

Some European diplomats have bemoaned a "Middle East fatigue" in the West that has also forced regional players to reconsider their relationships, leaving the door open for others to fill the void.

"The Iran-Saudi-China deal is symptomatic of our problems. Nobody saw it coming so we need to regroup collectively," said a second G7 diplomat.

A third Western diplomat said it was time for the G7 to take stock of the new dynamics in the region, noting that Saudi Arabian-led efforts to orchestrate OPEC oil cuts, against Western wishes, had been another signal.

The foreign ministers, who are preparing a heads of state summit in Hiroshima in mid-May, will centre their talks on nuclear non-proliferation and disarmament with North Korea, Iran and Russia in mind.

The war in Ukraine and how to prevent Russia from circumventing sanctions, the Indo-Pacific and more broadly how to tackle challenges to the existing international rules-based order would also be on the agenda, the French diplomat said.

"The G7 will only remain credible if it is able to handle the world’s problems," he said.