The United States, within the last two years, has sold nearly $1.5 billion in military equipment to Mexico, including millions of bullets, fleets of Black Hawk helicopters, and thousands of Humvees, reports Stars and Stripes.

Adm. William E. Gortney, the commander of U.S. Northern Command (Northcom), told lawmakers earlier this year that Mexico’s recent purchases represent a “100-fold increase from prior years.”

Northcom is the U.S. military headquarters that oversees Mexico.

Within the last two years, Mexico has purchased about $1.5 billion worth of equipment through America’s military sales program, 30 million bullets, two dozen UH-60 Black Hawk helicopters for its air force and navy, and more than 2,200 Humvees.

Since Mexican President Enrique Peña Nieto took office in December 2012, America’s southern neighbor has also spent an additional $2 billion on military equipment through U.S. private companies, Inigo Guevara Moyano, a D.C.-based Mexican defense consultant, told Stars and Stripes.

“All of these buys have been to replace existing systems that averaged 30 to 40 years old and drained budgets through high maintenance costs and poor availability,” said Moyano.

He pointed out that Mexico’s former president also increased defense spending, which shows a “maturing military-to-military relationship at the institutional level, regardless of who is in power.”

Mexico decided to reach out to the Pentagon about purchasing military equipment, a move that was praised by Adm. Gortney.

The admiral hailed Mexico’s decision to approach the U.S. Department of Defense (DoD) and described it as rare and “unprecedented,” marking a “historical milestone” in U.S.-Mexico relations.

“Americans and Mexicans familiar with the foreign military sales program said that the change in part reflects a revived security partnership between the two countries,” notes Stars and Stripes. “It also shows Mexico’s aggressive push to modernize its military in the face of powerful drug cartel adversaries.”

“Mexico’s long been suspicious of gringo motives (at least since it lost about half a million square miles of its territory to the U.S. in the 19th century) and has tended to not be a big U.S. military buyer, relying more on European equipment or private commercial agreements,” it adds. “At the start of President Enrique Peña Nieto’s term more than two years ago, his administration felt the United States had wormed its way too deeply into the drug war, and Mexico halted many security programs.”

The military equipment transaction between the two countries started with 27 rail cars carrying 30 million bullets into Mexico.

Soon after that load, fleets of Black Hawk helicopters and thousands of Humvees were transported to Mexico.

In total, about $1.5 billion worth of military equipment has gone to Mexico within the last two years, courtesy of the U.S. government’s military sales program.

Mexico asked the U.S. to fill a large order of $6 million worth of 5.56 mm bullets in late 2013, a request that the U.S. embassy in Mexico helped deliver within 100 days, a U.S. military official told Stars and Strip on condition of anonymity.

“That case really kind of broke the ice,” he declared. “They saw the responsiveness of what we could do as a partner in foreign military sales. And they liked it.”

The U.S. military sales to Mexico have not been immune to criticism.

“Some have been critical of the U.S. sales, particularly in a climate where Mexican security forces have regularly been accused of human rights violations,” mentions the Stars and Strips article.