Vulcan Materials and Sen. Katie Britt urged the Biden administration to protect the Birmingham-based company’s employees and gravel extraction pits that the Mexican government is threatening to forcefully seize, Vulcan said.

“We need your help to protect our employees and property rights, and the U.S.-Mexico cross-border trade relationship, while this process plays out,” J. Thomas Hill, chairman and chief executive officer of Vulcan Materials, wrote in a letter Wednesday to U.S. Ambassador to Mexico Ken Salazar.

Mexican President Andrés Manuel López Obrador threatened to declare the property a natural protected area or seize it by force if Vulcan doesn’t accept a $360 million offer for the gravel pits before he leaves office next year.

López Obrador has accused the company of extracting materials without the proper permits, Bloomberg news reported.

In March, the Mexican government seized the facility, despite a court ordered stay on any government action to confiscate the property.

Vulcan said the $360 million figure, calculated by a non-independent Mexican government organization, “represents a small fraction of our investments’ fair market value.”

The appraisal does “not take into account the value of our business as a whole, nor the value of the limestone reserves that we own, as has been shown in the ongoing NAFTA investment arbitration,” the company argues.

In the arbitration filing, Vulcan said it estimates the value of the nearly 6,000-acre property, located just south of the resort town of Playa del Carmen, at $1.9 billion.

In a letter dated Wednesday to Esteban Monteczuma Barragán, Mexico’s ambassador to the U.S., Hill said Vulcan has acted in good faith in negotiation’s with López Obrador, including proposing to transition the property to tourism development, which was among the Mexican government’s requests.

“We tried to work with you in a cooperative way and to accommodate your government’s requests,” Hill wrote to the ambassador.

“In response, your government suddenly shut us down and has continued to make disparaging and false public remarks against us. In our view, passing us documents purporting to contain a valuation based on an unclear methodology and representing only a fraction of the fair market value of our investments, along with a message that we should take it or face expropriation, is not a serious, good-faith negotiation or a reasonable attempt to fairly resolve the dispute.”

“We remain open to an eventual, mutually negotiated solution that would be satisfactory to both sides,” the CEO continued. “We welcome the opportunity to re-engage constructively toward that goal, in a context of mutual respect, and devoid of additional public disparaging and governmental measures against us—a long-standing, reliable and law-abiding investor in a foreign partner nation.”

Britt, who called the Mexican government’s March seizure of the property “unlawful and unacceptable,” said the latest development is a “stunt” that will only harm both the U.S. and Mexico.

“President López Obrador has already been caught using militarized force to seize this private property that Vulcan lawfully owns and operates in Mexico. Make no mistake, this latest transparent stunt is simply the most recent attempt in an ongoing scheme to bully this law-abiding American company out of the land and assets that it rightfully owns under Mexican law,” Britt said in a statement to AL.com.

“The result would be gravely detrimental to both Mexico and the United States, including jobs being lost and the American economy and supply chain for critical infrastructure projects being damaged. The Mexican government needs to follow its own system of laws, and the Biden Administration must send a clear, strong message that the United States will stand up for the rights of American businesses and individuals that lawfully operate abroad.”