Speaking on the sideline of the summit, held in the eastern city of Dhahran, OIC Secretary General Yousef Al-Othaimeen said that the status of Jerusalem was very important to the Arab and Islamic worlds, affirming that the Palestinian cause will remain as the chief issue for Arabs and Muslims, Kuwait News Agency (KUNA) reported.
King Salman also announced a $50 million donation to UNRWA, the United Nations agency for Palestinian refugees.
"We reiterate our rejection of the United States decision on Jerusalem", Salman said adding "East Jerusalem is an integral part of the Palestinian territories".
"East Jerusalem is an integral part of the Palestinian territories", he asserted.
Summits of the Arab League, established in 1945, rarely result in action.
Saudi Arabia, a long-time ally of the US, had also declared their support for Saturday's strikes on Syria by the US, UK and France, although the king did not mention this during his speech.
Arab League leaders on Sunday condemned the "criminal" use of chemical weapons in Syria and called for an global investigation, the Saudi foreign minister said.
He told Arab leaders that Iran was to blame for instability and meddling in the region.
Saudi Arabia's King Salman has criticised Donald Trump's decision to move the U.S. embassy in Israel from Tel Aviv to Jerusalem.More news: Justin Bieber punches man at Coachella party
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The image has slowly gained traction online and on social media by Arab users who said the image showed solidarity among Arab leadership.
Saudi Arabia's powerful Crown Prince Mohammed bin Salman, 32-year-old son of the king and de facto ruler of the world's largest exporter of oil, has said Assad will stay.
"We stress our absolute condemnation of the use of chemical weapons against the sisterly Syrian people and we demand an independent global investigation to guarantee the application of worldwide law to everyone proven to use chemical weapons", the group said in a statement.
The summit also comes with Saudi Arabia and Qatar locked in a monthslong diplomatic standoff, with Riyadh accusing Doha of supporting extremists and being too close to Iran.
Iran has been a key backer of Syrian President Bashar al-Assad, sending Shi'ite militias to fight alongside government forces. Doha denies the charges.
"We renew our strong condemnation of Iran's terrorist acts in the Arab region and reject its blatant interference in the affairs of Arab countries", he said.
Asked why Qatar was not on the summit's agenda, the Saudi foreign minister said: "Because Qatar is not on the agenda".
Tunisia will host the next Arab League summit in 2019.