Washington (CNN) Donald Trump said Tuesday he believes that invading Afghanistan in 2001 was a "terrible mistake," but he added U.S. troops need to stay in order to avoid a collapse of the government.

"We made a terrible mistake getting involved there in the first place," Trump said. "It's a mess, it's a mess and at this point we probably have to (leave U.S. troops in Afghanistan) because that thing will collapse in about two seconds after they leave."

While Trump has long called the Iraq War a mistake, his Tuesday interview on CNN's "New Day" appears to be the first time Trump has described the U.S. war in Afghanistan in the same terms.

While virtually all 2016 presidential contenders now say they believe the Iraq War was a mistake, none has lamented the U.S. incursion in Afghanistan following al-Qaeda's terror attacks on the World Trade Center and the Pentagon.

Trump's comments come as reports emerged Monday that President Barack Obama is considering leaving a sizable force of U.S. troops in Afghanistan next year despite his previous plans to withdraw from Afghanistan by the end of his tenure as president.

Read More