(CNN) Former Secretary of State John Kerry said Tuesday that he is going to think about a 2020 presidential bid, saying in response to a question about his plans that he was "not taking anything off the table."

"I've said I'm not going to eliminate, I'm not taking anything off the table," the 2004 Democratic presidential nominee said during an event at Harvard's Institute of Politics . "But I'm not sitting around -- I haven't been running around to the most obvious states, laying any groundwork or doing anything. Am I going to think about it? Yeah, I'm going to think about it, I've said that point blank."

During his remarks Tuesday, Kerry delivered a sharp criticism of the Trump administration on a series of issues including climate change and foreign relations.

"Simply because of all the things I've [talked] about. If you care about these things, you have to think about it. But I would love it -- I mean, I'm the guy who picked Barack Obama to give the keynote at my convention. And I kind of thought, it would be great if he re-nominated me four years later," Kerry said. "But it obviously worked out differently."

Kerry's comments come ahead of what is likely to be a large field of Democratic candidates vying to challenge President Donald Trump in 2020.

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