Prince Charles met the head of the world's largest Islamic grouping in the Red Sea city of Jeddah on Sunday, the Organisation of Islamic Cooperation said in a statement.
OIC Secretary General Ekmeleddin Ihsanoglu briefed Prince Charles "on the various intra-OIC programmes and activities in support of agricultural development, food security and drought resilience," it said.
Prince Charles and his wife Camilla embarked on a regional tour last week, beginning in Jordan.
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On Friday, Charles met Saudi billionaire Prince Alwaleed bin Talal and discussed Alwaleed's investments in Britain.
He also hailed King Abdullah's decision to appoint women to the Majlis Al-Shura (Consultative Council), the English-language Arab News quoting him as calling it "a vital step toward national participation in decision making."
Saudi Arabia, an absolute monarchy, imposes stringent restrictions on women, who are banned from driving and denied the right to travel without the consent of a male guardian.
Britain's royal couple will next travel to the Sultanate of Oman.