(CNN) -- A Mexican military helicopter hovered south of the border in the early morning darkness.
Below it, one of the country's most wanted drug lords was riding in a pickup truck.
Mexican authorities say they'd been tracking Zetas cartel boss Miguel Angel Treviño Morales for months. Early Monday morning, their moment came to swoop in.
The helicopter stopped the pickup Treviño was riding in 27 kilometers (about 16 miles) southwest of the border city of Nuevo Laredo, said Eduardo Sanchez Hernandez, the Mexican government's security spokesman.
Treviño, known as Z-40, had $2 million, eight weapons and hundreds of ammunition cartridges with him when he was captured around 3:45 a.m., Sanchez said.
The Zetas leader was in the pickup truck with two others, who were also arrested.
"It seems like one of them was in charge of financial operations of this gang and the other was a bodyguard," Sanchez said, adding that authorities would have more information after speaking with the suspects.
No shots were fired in the operation, said Sanchez, who didn't explain how the helicopter managed to stop the pickup.
"It made a maneuver that resulted in the truck stopping, and three people in the truck were apprehended by personnel on the ground who came to support the navy, which had made the detention using the helicopter," he said.
Treviño, 40, faces charges of organized crime, homicide, torture and money laundering, Sanchez said. There are at least seven arrest warrants for his capture.
Treviño is accused ordering the kidnapping and killing of hundreds of migrants in the border state of Tamaulipas, Sanchez said.
His arrest is the most significant blow to drug trafficking in Mexico since President Enrique Peña Nieto took office in December.
Mexican authorities had been offering a reward of 30 million pesos (about $2.4 million) and the U.S. State Department had been offering an award of up to $5 million for information leading to his capture.
In a news conference describing the dramatic military operation late Monday night, Sanchez said Treviño was known for "cruelty" and "the fury with which he attacked his victims."
The Zetas started out as the enforcement arm of Mexico's Gulf cartel, but later split off and formed their own drug trafficking organization.
They have since branched out into extortion, kidnapping and human smuggling.
The Zetas are accused of smuggling tons of cocaine and other drugs annually to the United States, generating many millions of dollars.
The name of the cartel conjures up some of the most violent images of the drug war: a casino fire that killed 52 people, the deaths of 72 migrants and tortured bodies hanging from bridges.
It's unclear how Treviño's arrest could affect the cartel.
Mexico's state-run Notimex news agency described Treviño as the head of the Zetas. But Sanchez did not mention the cartel's name during Monday night's news conference and did not describe Treviño as its leader.
Asked by a reporter Monday night who would head the organization after his capture, and whether Treviño's brother played a role in leading the cartel, Sanchez declined to comment.
Last year, Mexican authorities announced that they had killed Heriberto Lazcano Lazcano, who had been the cartel's leader.
The high-profile arrest of Treviño came the same day that Mexico's defense secretary and the head of Mexico's navy met with Gen. Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff.
A senior U.S. State Department official praised Mexican authorities for Monday's arrest.
"Credit goes to the Mexican government for this," the official said. "It is a very big get."
It is unclear whether the arrest will qualify for the U.S. government's reward program, the official said.
"We work well with these guys and congratulate them," the official said.
CNN's Elise Labott, Mariano Castillo, Ariel Crespo, Michael Roa and Chandler Friedman contributed to this report.