Mayor Pete Buttigieg criticized President Donald Trump and Vice President Mike Pence after they left a United Nations climate summit early on Monday.

Buttigieg described Trump and Pence as the “end of American leadership” in the world.

This is what the end of American global leadership looks like. pic.twitter.com/OmxrIDZYr9 — Pete Buttigieg (@PeteButtigieg) September 23, 2019

Trump, who was not scheduled to attend the summit, surprised government leaders after arriving to listen to a speech given by Indian Prime Minister Narendra Modi and German Chancellor Angela Merkel.

Pence and Trump left after about ten minutes to host a panel event of their own on the importance of religious freedom.

Earlier in the day, Buttigieg criticized the president for failing to address the issue of climate change, calling it the “global security challenge of our era.”

The South Bend Mayor is currently on a bus tour of Iowa and criticized the president as the United Nations summit began in New York City.

“I am very nervous about how the U.S. is going to look at the U.N. General Assembly that is going to convene right here in the United States,” he told voters in Iowa Falls on Monday. “Will it be one more time where the seat for U.S. leadership is empty? Or are we going to demonstrate that we’re a country that keeps its word and is prepared to lead?”