German Chancellor Friedrich Merz expressed skepticism over the effectiveness of the U.S. and Israeli war against Iran, warning that attempts at regime change are unlikely to succeed.

"Is regime change really the goal?" he said at a forum in Frankfurt organized by the FAZ newspaper. "If that's the goal, I don't think you'll achieve it. It's mostly gone wrong" in past conflicts, he said, pointing to the Afghanistan war.

Merz also questioned the effectiveness of the U.S.-Israeli war in Iran.

"I'm just not convinced that what Israel and the U.S. are doing right now will actually succeed," he said.

"I have serious doubts about whether there is a strategy and whether that strategy is being implemented successfully. In that regard, it could take longer, and things probably won't improve," he added.

Merz said Americans and Israelis "are becoming more deeply entangled in this conflict every day."

He warned that the U.S. and Israel would not be able to achieve regime change if that is their objective.

The chancellor also said U.S. President Donald Trump has understood that the Iran war is not NATO's war.

"I believe that at least the U.S. government – and probably the president as well – has now accepted that we cannot support this. But we have, of course, offered to organize, for example, military protection of the Strait of Hormuz together with others in the event of a ceasefire," Merz said.

"This requires an international mandate. It requires approval from the German Bundestag (parliament) and a prior cabinet decision. We are far from that, and as long as the war continues, it is not an option for us either," he added.

Hostilities have escalated since U.S.-Israeli strikes on Iran began on Feb. 28.

Iran has retaliated with repeated drone and missile strikes targeting Israel and Gulf countries hosting U.S. military assets.