Against a backdrop of black helicopters at an air base, police presented Moises Montero Alvarez, known as "El Koreano," and described him as a leader of a violent splinter group that's wreaking havoc in the resort of Acapulco.

Later in the morning, National Security spokesman Alejandro Poire said that a series of arrests — most notably of a chief enforcer for the Juarez Cartel who police say acknowledges ordering 1,500 murders — had delivered crippling blows to organized crime in Mexico.

"In recent weeks, we Mexicans have been witnesses to the systematic weakening of all criminal organizations," Poire said.

Poire highlighted the capture last Friday of Jose Antonio Acosta, a 33-year-old former state policeman who rose to become the alleged boss of La Linea, the Juarez Cartel's enforcement wing, which has turned Ciudad Juarez, along the border with Texas, into the hemisphere's most murderous city.

Acosta's group oversaw "the worst surge of violence that our nation has seen in recent years," Poire said. He added that the arrest "weakens the ability of this group to carry out kidnappings, murders, extortion and the smuggling of drugs to the United States."

U.S. prosecutors are expected to file an extradition request to try Acosta in the United States on charges of involvement in the killings last year of an American consulate employee, her husband and the husband of another consulate worker in Ciudad Juarez.

Observers said the threat of facing U.S. justice might compel Acosta to rat out corrupt former and active-duty Juarez police officers who are thought to compose much of La Linea, which is battling the rival Sinaloa cartel for control of Juarez, across the Rio Grande from El Paso, Texas.

"This could be a pivotal point in the battle for control of Juarez, and developments there must be watched very carefully in the coming days and weeks," the firm Strategic Forecasting of Austin, Texas, said in a note to clients.

But even amid the spate of arrests, Mexican authorities faced fresh doubts about their ability to keep suspects in custody and carry off successful prosecutions.

Last week, an accused midlevel boss for the Sinaloa drug cartel, Hector Eduardo Guajardo, climbed out the window of a hospital in Mexico City, escaping police guards. Poire called the escape "absolutely and entirely reprehensible."

Poire refused to shed much new light on upheaval in the attorney general's office, which announced Monday that 21 of the nation's 31 top state and federal district prosecutors had submitted their resignations.

"The attorney general will undertake all necessary replacements of functionaries to improve the access to justice that Mexicans demand," Poire said, suggesting that the resignations were forced.

He said it was up to Attorney General Marisela Morales to decide whether any of the resigning prosecutors should be investigated for corruption.

Since taking office in April, Morales has led a purge, removing 462 officials from their posts and initiating charges against 111 others for crimes such as fraud, robbery and abuse of power.

President Felipe Calderon's government has been repeatedly embarrassed by its inability to prosecute corruption and racketeering cases.

Two weeks ago, prosecutors were forced to free the former mayor of Cancun, Gregorio Sanchez, when the drug prosecution against him crumbled 14 months after his arrest.

In his news conference Tuesday, Poire highlighted the arrests of other accused crime bosses in the past month, including:

• Jesus Rejon Aguilar, nicknamed "El Mamito," or Pretty Boy, the reputed No. 3 leader of Los Zetas, a transnational crime group known for beheading its foes. The U.S. government had offered up to $5 million as a reward for his capture.
• Nery Salgado Harrison, nicknamed "Yupo," a local head of a newly formed group, the Knights Templar, that's arisen in the state of Michoacan, home to the now-fractured La Familia crime group.