President Trump told senior aides late Tuesday that he approved of attack plans for Iran, but was holding off on giving the final order to see if Tehran will abandon its nuclear program, three people familiar with the deliberations said.

Since his private instructions in the White House Situation Room to the military, Trump has disclosed publicly that an attack is an option.

“I have ideas on what to do but I haven’t made a final—I like to make the final decision one second before it’s due,” he told reporters Wednesday.

Trump is hoping that threatening to join Israel’s strikes on Iran, which continued for a sixth day, will compel Tehran to meet his demands, the people said. He acknowledged that a U.S. attack was under consideration but said he still may decide against it.