Iran’s president vowed Saturday that the country would never surrender, as Israel launched a major wave of airstrikes, including attacks that set one of Tehran's main airports on fire.

The wave of pre-dawn Israeli raids was one of the biggest since the bombing campaign began last Saturday, with a military academy, an underground command centre and a missile storage facility named as targets.

AFP photos showed fire and smoke billowing from Tehran's Mehrabad International Airport, one of two that serve the capital.

But President Masoud Pezeshkian struck a defiant tone in a speech broadcast on state TV in which he appeared to address U.S. President Donald Trump, who said Friday that only Iran's "unconditional surrender" could end the war.

Iran's enemies "must take their wish for the unconditional surrender of the Iranian people to their graves," Pezeshkian said, in a speech broadcast on state TV.