The US offer includes Marshals, drones, and a special task force to hunt down Joaquín "El Chapo" Guzmán Loera after he escaped from a maximum security Mexican prison last weekend.
President Enrique Pena Nieto's administration has reportedly not responded, and even Mexican officials are confused.
"We can't really understand why [top Mexican officials] are refusing to give an answer," a Mexican official, who works in the country's security apparatus, told the Times. "We're just on standby."
El Chapo's brazen escape and the subsequent response highlight the deterioration of US-Mexico relations under Peña Nieto.
Since taking office in 2012, Peña Nieto has all but ended the practice of extraditing cartel leaders to the US in an attempt to curb Washington influence in fighting the drug war in Mexico.
"The Mexicans think we are domineering and imperialist, and we think they are corrupt," Adam Isacson, a senior associate for regional security at the Washington Office on Latin America, told the Times.
The US repeatedly asked to have the kingpin extradited, arguing that it's counterproductive to jail these drug lords in a place where they have access to their entire criminal network - including corrupt prison guards.
To that point, Mexico's interior minister said that Guzman "had to have" had help to escape from prison officials.
El Chapo's second escape since 2001 came a little over a year after Peña Nieto himself promised that "what happened last time would not be repeated."
AP/Eduardo Verdugo Joaquin "El Chapo" Guzman
The Mexican president's words came back to haunt him last Saturday, when Guzmán slipped down a shaft into a mile-long ventilated tunnel constructed over the course of a year and vanished into his countrywide support network.