President Trump weighed in on General Motors announcement of layoffs and plant closures and on the recent climate assessment as he was departing for rallies in Mississippi Monday.

He said he's "not happy" with GM and also told reporters that he spoke with the U.S. auto giant's CEO, Mary Barra, when he found out about the cuts. Mr. Trump said he "was very tough," and he reminded her, "This country has done a lot for General Motors. We'd better get back in there soon -- that's Ohio," where one of the plants likely to close is located. That plant, in Lordstown, Ohio, is where the Chevy Cruze is produced. Barra announced that GM is discontinuing several car models, including the Volt, Impala and Cruze in the U.S. Mr. Trump said the Chevy Cruze, "is not selling."

The president, when asked about the catastrophic economic consequences predicted by the recent National Climate Assessment, responded, "I don't believe it," and he claimed, "Right now we're at the cleanest we've ever been and that's very important to me."

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The most recent climate assessment, compiled by 13 government agencies, suggests the U.S. faces severe economic consequences -- billions of hours in lost productivity -- as well as more extreme weather and tens of thousands of deaths, by the end of the 21st century if the world does not address climate change.

Mr. Trump also fielded a question on the recent skirmishes on the southern border between migrants and federal law enforcement. He denied that the border patrol was using tear gas on children. "They're not. They had to use because they were being rushed by some very tough people and they used tear gas," he said. "Here's the bottom line: No one is coming into our country unless they come in legally."

Mr. Trump is holding two rallies for Sen. Cindy Hyde-Smith Monday — one in Tupelo, Mississippi, and then one 300 miles to the south in Biloxi, Mississippi. Mississippi voted overwhelmingly for the president in 2016. Hyde-Smith was appointed U.S. senator for the state after former Sen. Thad Cochran was forced to leave his seat due to deteriorating health.

Arden Farhi contributed to this report.