President Trump, Rubio warn Iran 'hardest hits are yet to come'

President Donald Trump and Secretary of State Marco Rubio issued stark warnings to Iran Monday that the "hardest hits" in its new conflict in the region is still to come if it does not agree to end its nuclear program.

The United States and Israel launched missiles at Iran over the weekend, which resulted in the death of Iranian Supreme Leader Ayatollah Ali Khameini. Iran has since retaliated by targeting Israel and U.S. bases in several Middle Eastern countries.

Trump told CNN that he thinks the U.S. side of the conflict is "going very well," and warned Iran that bigger hits could still be coming.

“We’re knocking the crap out of them,” Trump said. “We’ve got the greatest military in the world and we’re using it ... We haven’t even started hitting them hard. The big wave hasn’t even happened. The big one is coming soon.”

The president also commented that the U.S. was ahead of schedule in the amount of damage it has caused Iran, but that he anticipates the attacks will last approximately one month.

Rubio echoed the president's comment, stating that the next phase of U.S. attacks on Iran will be "more punishing" than the ones they have dealt it so far.

"The hardest hits are yet to come from the U.S. military. The next phase will be even more punishing on Iran than it is right now," Rubio told reporters. "The objectives of this operation are to destroy their ballistic missile capability and make sure they can't rebuild it, and make sure that they can't hide behind that to have a nuclear program."

The State Department has urged Americans currently in the Middle East to leave their respective countries in light of the escalating conflict.