Vice President Joe Biden is changing his story about his role in the raid that killed Osama bin Laden.

At an event honoring Walter Mondale in Washington, Biden spoke about the process in the months leading up to the May 2011 operation by a group of Navy Seals.

Biden, who's weighing a run for president, said that during a closed-door meeting with President Barack Obama and other players involved, such as then Secretary of Defense Robert Gates and former CIA director Leon Panetta, he expressed caution about the mission, but when he met with Obama later, he was more confident.

"I told him my opinion. I thought he should go, but to follow his own instincts," Biden said.

Previously, Biden said he was against the raid to get bin Laden and advised the president against it. In her 2014 autobiography, presidential candidate Hillary Clinton said Biden was skeptical and she was fully supportive of the mission.

During the panel discussion at George Washington University, Biden portrayed himself as a loyal and vital part of Obama's administration who was involved in key issues during the past seven years.

"We've had two great secretaries of state," Biden said, but he pointed out that when the vice president speaks with a foreign leader, they know that "I am speaking for the president."

Biden is expected to announce if he intends to make a third try for the Democratic nomination by the end of the week, according to people close to him.