A professor specializing on the Middle East says regime change is “unlikely” after U.S.-Israeli airstrikes were launched against Iran on Saturday.

Sina Azodi, of The George Washington University, told WTOP that “a lot of people are hopeful, but you’re talking about a regime that was born into a revolution.”

The joint strike efforts have led to the deaths of high-ranking Iranian officials, including Iran’s Supreme Leader, Ali Khamenei.

“It survived many political assassinations in its early years,” Azodi said in an interview with WTOP’s Sarah Jacobs. “At the same time, it was fighting a total war with Iraq from 1980 to 1988. So it’s quite resilient, that’s one issue we have to keep in mind.”

Listen to the full interview:

With Khamenei dead, Iranian Foreign Minister Abbas Araghchi said a new supreme leader will be chosen in “one or two days.”

President Donald Trump has made it clear he wants a regime change in Iran. A senior White House official said “new potential leadership” in Iran has suggested they are open to talks with the U.S.

The U.S.-Israeli airstrikes continued Sunday and have led to multiple attacks on several countries in the region, with bombs dropping and killing more than 200 people since the start of the strikes, according to Iranian leaders.

Iran fired retaliatory strikes at Israel and toward U.S. military installations around Gulf Arab states. In Dubai, three U.S. service members were killed, marking the first known American casualties from the conflict. Five service members were injured.

Tensions between the U.S., Israel and Iran have remained ongoing for decades, since Iran’s 1979 Islamic Revolution. Conflict has largely centered around Iran’s nuclear enrichment program as global leaders grow concerned with the possibility of Tehran securing nuclear-grade weapons.