US President Donald Trump called for Iran's "unconditional surrender" on Tuesday following an almost week-long conflict between Israel and Iran.

This move, alongside the build-up of US troops in the region, could indicate an imminent escalation in the Israel-Iran air war, an analyst told Reuters, possibly including direct U.S. military action.

“Right now, we are most likely the hours before a major escalation, rather than de-escalation. What Trump has been signaling, tweeting today, does not seem to suggest that he has any plans to actually give diplomacy a real chance. He's calling for surrender,"  said Trita Parsi, executive vice president of The Quincy Institute and Iran expert.

"I think he is likely miscalculating, thinking that the Iranians believe that surrender actually is an option, that Trump would honor the terms of a surrender. That's assuming that they even think that surrender is in the cards in the sense that their assessment of their strength and weakness is likely very different from the perception that exists in Israel and in the United States," he added.

Meanwhile, Iran's Supreme Leader Ayatollah Ali Khamenei also posted on X saying "We must give a strong response to the terrorist Zionist regime. We will show the Zionists no mercy."