WASHINGTON -- Wisconsin Gov. Scott Walker (R) said over the weekend that the next president of the United States needed to be prepared to take aggressive military action on their very first day in office, including against Iran.

The presidential contender, who had promised to "terminate" the nuclear agreement with Iran upon his inauguration, made the remark while speaking with reporters at the Family Leadership Summit in Ames, Iowa, on Saturday. Walker was asked about a criticism from former Florida Gov. Jeb Bush (R), who asserted during a town hall last week that unwinding the agreement on day one was an unrealistic promise.

One thing that I wont do is just say, as a candidate, Im going to tear up the agreement on the first day, Bush said in Nevada on Thursday. First, said Bush, he needs to have his team in place. "Thats great, that sounds great but maybe you ought to check in with your allies first, maybe you ought to appoint a secretary of state, maybe secretary of defense, you might want to have your team in place, before you take an act like that.

Asked about Bush's remarks on Saturday, Walker argued -- without mentioning Iran directly -- that a president ought to be ready to take action from the moment they step foot into the Oval Office.

"He may have his opinion. I believe that a president shouldn't wait to act until they put a cabinet together or an extended period of time, I believe they should be prepared to act on the very first day they take office," he said. "It's very possible, God forbid that this would happen, but very possible, that the next president could be called to take aggressive actions, including military actions, on their very first day in office."

After Walker aides accused Bush of softening on his opposition to the agreement, the former Florida governor issued a statement to The Weekly Standard assuring that he would begin immediately to responsibly get us out of this deal.

The dispute between the two early GOP frontrunners comes just weeks before the first debate, hosted by Fox News in August. It also follows Walker's efforts to bone up on foreign policy, positioning himself as one of the most hawkish candidates in the 2016 Republican presidential field. Addressing conservatives at the Family Leadership Summit on Saturday, Walker said the U.S. needed "a foreign policy that puts steel in the face of our enemies," and one that unapologetically asserted power across the globe.