US President Barack Obama confessed on Sunday that the worst mistake he made during his eight years in the White House was failing to plan for the aftermath of the NATO-led military intervention of Libya in 2011.

The nation went into a state of complete chaos after the NATO forces pulled out. It now has two conflicting governments claiming authority over the country and the extremists with unprecedented powers. “Probably failing to plan for the day after what I think was the right thing to do in intervening in Libya,” the Fox News quoted him as saying in an interview on Sunday.

This is not the first time the president mentioned Libya and the NATO-led intervention in the recent weeks. In a piece published in The Atlantic last month, he said that the UK Prime Minister, David Cameron, became preoccupied in a “range of other things” after the operations.

Though Obama considered the operation to be successful, he now sees Libya in a complete mess. The inability to plan for the aftermath of the intervention is the worst mistake the president believes he made during his eight-year tenure.

The US decided to join the coalition of the European and Arab countries to protect the Libyan people from then Libyan Dictator Muammar Gaddafi’s violent threat. The dictator, who was intolerant towards dissent, threatened to “cleanse Libya house by house” after his people started demanding change.

The NATO coalition, which operated under the UN Security Council approval, installed a no-fly zone over Libya and bombed Gaddafi’s military establishments. Months later, Gaddafi was overthrown and killed. A transitory government was formed in place of his regime, the Huffington Post reported.

Five years have passed since then and Libya is now in a state of civil war. The current condition of the country prompted a renewed debate on whether the military intervention of 2011 can be called a successful mission. In September 2015, Obama criticised the Libya intervention in a speech before the UN General Assembly.

“Our coalition could have and should have done more to fill a vacuum left behind,” he had said, as quoted by the CNN.