MEXICO CITY – Mexican President Claudia Sheinbaum said on Saturday that U.S. President Donald Trump proposed sending American troops into Mexico to help her administration fight drug trafficking but that she rejected it.

Her remarks to supporters in eastern Mexico came in response to a Wall Street Journal article published the day before, describing a tense phone call last month in which Trump reportedly pressured her to accept a bigger role for the U.S. military in combating drug cartels in Mexico.

“He said, ‘How can we help you fight drug trafficking? I propose that the United States military come in and help you.’ And you know what I said to him? ‘No, President Trump.'”

She added: “Sovereignty is not for sale. Sovereignty is loved and defended.”

White House National Security Council spokesman James Hewitt said in a statement later Saturday that Trump has worked closely with Mexico’s president “to achieve the most secure southwest border in history.”

“Dangerous Foreign Terrorist Organizations, however, continue to threaten our shared security and the drugs and crime they spread threaten American communities across the country,” the statement said. “The President has been crystal clear that Mexico must do more do combat these gangs and cartels and the United States stands ready to assist and expand the already close cooperation between our two countries.”

The U.S. military presence has increased steadily along its southern border with Mexico in recent months, following Trump’s order in January to increase the army’s role in stemming the flow of migrants.

The U.S. Northern Command has surged troops and equipment to the border, increased manned surveillance flights to monitor fentanyl trafficking along the border and sought expanded authority for U.S. Special Forces to work closely with Mexican forces conducting operations against cartels.

Trump designated many of the gangs and cartels smuggling drugs into the U.S. as foreign terrorist organizations on Feb. 19, restricting their movements and lending law enforcement more resources to act against them.

But Sheinbaum’s hardline stance Saturday signaled that U.S. pressure for unilateral military intervention would put her and Trump on a collision course after months of cooperation on immigration and trade.

“We can work together, but you in your territory and us in ours,” Sheinbaum said.