Biden visited Abu Dhabi's Sheikh Zayed Grand Mosque on Monday morning, pausing outside to remove his black dress shoes in keeping with Islamic custom.
He examined a wall in the ornate mosque bearing the 99 names of God written in Arabic before stepping outside to wave at visiting tourists kept a short distance away.
Accompanying Biden on the mosque tour was its director-general, Yousif Abdallah Alobaidli, and Minister of State Reem al-Hashimi.
Biden is on a regional tour that will also include visits to Israel, the West Bank and Jordan.
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