U.S. ground troops will immediately be ordered to engage in a ground battle against the Islamic State militants in Syria and Iraq if the terrorist organization ever manages to get hold of a nuclear weapon, President Barack Obama said for the first time since the start of then anti-ISIS offensive dubbed Operation Inherent Resolve.

Although Obama had previously been unwavering and adamant in his stance to refrain from deploying the U.S. army into ISIS territory, he claimed that it would all change if the terror group was discovered to have nuclear capabilities, ABC News reported.

"There are always circumstances in which the United States might need to deploy U.S. ground troops," the Commander-in-Chief told reporters at a news conference in Brisbane, Australia, on Sunday.

"If we discovered that [ISIS] had gotten possession of a nuclear weapon, and we had to run an operation to get it out of their hands, then, yes, you can anticipate that not only would Chairman Dempsey [the top U.S. general] recommend me sending U.S. ground troops to get that weapon out of their hands, but I would order it," he added.

The troublesome scenario was brought up to illustrate that certain circumstances do exist where the U.S. would be forced to issue a "boots on the ground' operation against ISIS in Iraq and Syria. Currently, around 1,500 U.S. troops are due to be deployed in Iraq where they are expected to "advise" Iraqi forces, but not engage in actual combat, according to UK MailOnline.

Even though there have been no indications that ISIS currently possesses or might obtain a nuclear weapon in the future, Obama's declaration of a nuclear weapon in the hands of ISIS is a noteworthy new "red line" - and a very high bar for a U.S. offensive role on the ground, according to ABC News.

Ever since anti-ISIS military operations began, Gen. Martin Dempsey, chairman of the joint chiefs and Obama's top military adviser, has consistently kept the door open to deployment of U.S. ground troops in combat situations, but has yet to formally recommend it.

Last week, Dempsey testified on Capitol Hill that the Pentagon is "certainly considering" a recommendation for the president to send combat troops.

"Yes, there are circumstances in which [Dempsey] could envision the deployment of U.S. troops. That's true everywhere, by the way," Obama said Sunday. "That's his job, is to think about various contingencies. And, yes, there are always circumstances in which the United States might need to deploy U.S. ground troops."