President Donald Trump’s emerging Iran deal is facing strong pushback from several Republican lawmakers and former officials who argue it could leave Iran stronger and undermine recent U.S. military gains.

Senators including Ted Cruz, Lindsey Graham, and Roger Wicker warned that easing pressure on Tehran or allowing continued nuclear activity would be a major strategic mistake.

Trump defended the negotiations, saying the deal is not finalized and criticizing opponents while insisting it will prevent Iran from obtaining a nuclear weapon.

He also said any agreement would differ from the Obama-era nuclear deal he previously withdrew from, and that sanctions and pressure would continue until terms are fully reached, PBS has reported.

While some Republicans like Senator Rand Paul support giving diplomacy a chance, the proposal remains highly controversial as details continue to emerge.