Saudi Arabia's King Salman on Sunday opened an Arab League summit by criticising US President Donald Trump's decision to transfer the US embassy in Israel from Tel Aviv to Jerusalem.
"We reiterate our rejection of the US decision on Jerusalem," the king said in a speech in Dhahran in eastern Saudi Arabia.
"East Jerusalem is an integral part of the Palestinian territories," he added.
The move has sparked deep anger among the Palestinians, who see East Jerusalem as the capital of their future state, and across the Arab world.
The King announced a $150-million (120 million euro) donation for the maintenance of Islamic heritage in East Jerusalem.
"Saudi Arabia announces a $150-million grant to support the administration of Jerusalem's Islamic property," the monarch said at the opening of the Arab League summit in the kingdom's eastern city of Dhahran.
Islamic holy sites in the city, including the revered Al-Aqsa mosque, are administered by a Jordanian-run trust known as the Waqf.
King Salman also announced a $50 million donation to UNRWA, the UN agency for Palestinian refugees.
The organisation, which provides aid to more than three million people, faces serious financial difficulties after the US announced it was cutting its funding of the body.
In mid-March, UNRWA said it did not have the necessary funds to continue running until the summer.
UNRWA head Pierre Krahenbuhl recently said the agency was seeking $441 million to continue operating, but that donors had only pledged $100 million.