Mexican President Claudia Sheinbaum rebuffed President Donald Trump‘s push for U.S. troops to cross the border into Mexico to help fight the drug cartels.

Calling Sheinbaum a “lovely woman”, Trump nevertheless confirmed that his proposal was snubbed as he spoke with reporters on Air Force One on Sunday while flying back to Washington, DC.

The president said it was “true” he made the pitch. He said he came up with the idea because the cartels “are horrible people that have been killing people left and right.”

Trump said the cartels have made a fortune “on selling drugs and destroying our people” and that if Mexico wanted help with the cartels, he would be “honored to go in and do it.”

His comments came after Sheinbaum revealed that she had soundly dismissed the idea of U.S. troops entering her country.

“He said ‘How can we help you fight drug trafficking? I propose that the United States military come in and help you,’” she recalled on Saturday.

Sheinbaum said she told the president no, “Sovereignty is not for sale. Sovereignty is loved and defended.”

She added that she proposed that the two countries work together but “with you in your territory and us in ours.”

The comments by both world leaders confirmed a proposal first reported by the Wall Street Journal last week. It said the offer was made during a tense 45-minute phone conversation on April 16.

Speaking to reporters on Sunday, Trump praised the president of Mexico as a “lovely woman” but he claimed that she was “so afraid of the cartels that she can’t even think straight.”

However, this is not the first time Sheinbaum has rejected a Trump proposal since he was elected to a second term.

Unlike some other world leaders, including those in Canada, the 62-year-old Mexican leader appears to be having much more success in standing up to the president without provoking his wrath.

In January, Sheinbaum offered up a sarcastic response to Trump’s call for the Gulf of Mexico to be renamed the “Gulf of America.”

She also managed to successfully shield Mexico, at least temporarily, from the president’s threat to impose sweeping 25 percent tariffs on Mexican imports as he pushed the southern neighbor to do more to combat the flow of fentanyl across the border into the U.S.

At the same time, the president also reversed course last week to slap tariffs on auto parts manufactured south of the border.