Donald Trump’s election generated concern in the Middle East over his stance on Muslims and immigrants as well as uncertainty about how the president-elect will navigate the tangled web of regional alliances and execute the policy objectives he has set out.

Mr. Trump has said he opposes the hard-fought deal to rein in Iran’s nuclear program that President Barack Obama negotiated. But he has also promised to improve Washington’s relations with Moscow, a major ally of Tehran.

The Republican party leader promised to work with Middle East allies to defeat Islamic State. But in the same breath, he berated Saudi Arabia—a key member of the U.S.-led alliance fighting the terror group.

Iranian President Hassan Rouhani said after the vote that the nuclear deal was irreversible as it was negotiated with several countries and endorsed by a United Nations Security Council vote.

“The U.S. elections result will not have any impact on the Islamic Republic’s policies,” Mr. Rouhani said in comments carried by state television. “Today, the U.S. is definitely not more capable than before…of creating global consensus against Iran.”