Iran’s supreme leader suggested that his country would pursue nuclear negotiations with the United States, telling the country’s government there was “no barrier,” to discussions with the “enemy,” in a video broadcast on state television Tuesday.

It was unclear if Ayatollah Ali Khamenei was signaling anything more substantive than the back-channel talks the United States and Iran have held recently on the status of Tehran’s nuclear program and Western sanctions.

His comments, including a warning against trusting the United States, came during a meeting with the cabinet of President Masoud Pezeshkian of Iran, the newly elected reformist leader, amid rising tensions between Iran and Israel.

“It is not contradictory to engage the same enemy in some places, there’s no barrier,” Mr. Khamenei said in the video. “The issue is that we should not pin our hope to the enemy and trust him.”

Dr. Pezeshkian, a cardiac surgeon, won office in a special election held in June after his predecessor, Ebrahim Raisi, died in a helicopter crash. Mr. Raisi was seen as more of a hard-liner, in step with the Shiite Muslim clerics who rule the country, and as a potential successor to Mr. Khamenei as supreme leader.

It remains unclear whether Iran’s change in leadership and the approaching election of a new U.S. president in November could presage a shift in relations between the two countries. But Mr. Khamenei holds the ultimate say in Iran’s government, and the extent to which Dr. Pezeshkian will be able to steer foreign policy is yet to be seen.