Iran’s supreme leader admonished the West and Israel on Wednesday not to seek advantage from the antigovernment uprisings convulsing the Arab Muslim world, delivering the warning in a nationally broadcast speech that appeared to reflect new unease in Tehran over the course of events among its strategic neighbors, particularly Syria.

The speech by the leader, Ayatollah Ali Khamenei, given at Tehran University to commemorate Id al-Fitr, the Muslim holiday, was officially described in Iran’s state-run press as a respectful tribute to the revolutionary movements that have reawakened Muslim populations to “their genuine Islamic identity.”

But the speech included a cautionary caveat that suggested Iranian leaders are worried about the possibility of outcomes that diminish their influence as these movements progress.

“The events taking place in Egypt, Tunisia, Yemen, Libya, Bahrain and certain other countries today are decisive and destiny making for the Muslim nations,” the ayatollah said. However, he said, “if the imperialist and hegemonic powers and Zionism, including the U.S. tyrannical and despotic regime, manage to use the ongoing conditions in their own favor, the world of Islam will definitely face big problems for tens of years.”