Iran’s president visits Saudi Arabia for the first time since the two mended ties.

President Ebrahim Raisi of Iran arrived in Saudi Arabia on Saturday for a summit on the war in Gaza, his first visit since the regional rivals agreed early this year to restore diplomatic ties after years of hostility.

Saudi Arabia had initially scheduled two summits over this weekend, one for members of the Organization of Islamic Cooperation and the second for the Arab League. But they were combined into one event on Saturday. Representatives from Egypt, Jordan, Lebanon, Turkey and Iraq were also expected to attend.

The leaders, who worry that the unrest will spill across the region, are expected to call for an immediate cease-fire in Gaza and the provision of more desperately needed humanitarian aid, as well as a restart to peace talks for a lasting solution.

The war was set off by an Oct. 7 attack on southern Israel by Hamas, the armed Palestinian group that controls Gaza, which killed roughly 1,200 people, according to Israeli officials. Israel has since bombarded Gaza with thousands of airstrikes, laid siege to the territory by cutting off water, food, fuel and other basic necessities, and launched a ground invasion. The war has killed more than 10,000 Palestinians, many of them children and women, according to the Gaza health ministry.

Mr. Raisi’s trip follows a significant pivot in March, when Iran and Saudi Arabia agreed to reopen embassies in each other’s countries and to revive a security pact in a deal brokered by China.

The rivalry for dominance between the two Middle Eastern powers has long shaped regional politics and trade. It has predominantly played out via proxy conflicts in Yemen, Iraq and Lebanon, where Iran has supported militias that Saudi officials say have destabilized the region.

Mr. Raisi was expected to address the Saudi summit, and met with the Qatari emir, Sheikh Tamim bin Hamad al-Thani, on the sidelines, the Iranian state news media reported.