It comes after Israel says it was targeted by fresh Iranian attacks. Meanwhile, the US moves to ease sanctions on some Russian oil to curb price rises.

The message from Mojtaba Khamenei was read by a presenter on Iranian state TV. He has not been seen in public since succeeding his father.

The Iran conflict is driving up energy and fertilizer costs, raising alarms over a return of food inflation. Farmers are bracing for resource shortages that could drag down harvests.

In the United States, the average price for a gallon of regular gas is about $3.61, up about 31 cents from last week, according to GasBuddy.