But even as he rolled out a crime prevention program last week and declared it the government’s new priority, a rash of high-profile mayhem threatened to undercut his message and raise the pressure to more forcefully confront the lawlessness that bedeviled his predecessor.

The southwestern state of Guerrero, long prone to periodic eruptions of violence, has proved a challenge once again. Gang rapes of several women have occurred in and around the faded resort town of Acapulco, including an attack this month on a group from Spain that garnered worldwide headlines, and an ambush killed nine state police officers in a mountainous no-man’s land. Out of frustration that the state was not protecting them, rural towns in Guerrero have taken up arms to police themselves.

Elsewhere, grenades were set off this month near the United States Consulate in the border town of Nuevo Laredo during a battle among gangs, and 17 members of Kombo Kolombia, a folk band in northern Mexico, were kidnapped and killed last month.

The bloodshed continued despite some indications that the violence leveled off last year, according to a report released on Feb. 5 by the University of San Diego’s Trans-Border Institute, which analyzed a range of government homicide statistics. Mr. Peña Nieto’s government also released statistics this month that it said showed that homicides presumably related to organized crime had dipped from December to January, but analysts have long questioned how those numbers were compiled, given the chronic lack of criminal investigations.

Still, the appetite of criminal groups for shocking violence seems unabated and presents a challenge for the president. Can he manage to avoid being drawn into the iron-fisted approach of his predecessor and effectively change the focus of the national discussion to other matters, like the economy?

“They are trying to have the president not use the crime issue as his political priority,” said Ana Maria Salazar, a security analyst who worked in the American government and now hosts a radio show here. “But at the same time, it doesn’t seem what they are talking about is confronting or going to have an impact on the current violence and criminal organizations.”

She added, “They haven’t laid out what they are going to do in the short term to retake Mexican territory in control of criminal organizations.”

Government officials have asked for patience, saying Mexico’s crime problems cannot be solved overnight.

They have made it clear that they want to break with the approach of former President Felipe Calderón, who heavily enlisted the military and the federal police against crime gangs, but the new government has taken a similar tack in recent flare-ups, including sending a cadre of federal police officers to Acapulco after the attacks there. Government officials have pledged closer coordination between the federal police and the state authorities.

Officials are promoting the less militaristic crime prevention program introduced last week as a linchpin, with Mr. Peña Nieto personally announcing it and Interior Secretary Miguel Ángel Osorio Chong briefing reporters extensively on it. On Thursday, an under secretary presented a slick brochure on the program to foreign journalists and answered questions for 45 minutes.

“It’s clear that we must put special emphasis on prevention, because we can’t only keep employing more sophisticated weapons, better equipment, more police, a higher presence of the armed forces in the country as the only form of combating organized crime,” Mr. Peña Nieto said in announcing the program in Aguascalientes, one of the more peaceful precincts in the country.

The program calls for creating an interagency commission that would spend $9 billion in the coming years in 250 of the most violent cities and towns, beginning with the worst. The plan envisions longer school days, drug addiction programs and other social efforts in addition to public works projects, but officials said specifics were still being worked out and would be detailed later.

It resembles a plan Mr. Calderón put in place a few years ago for Ciudad Juárez, one of the bloodiest cities in Mexico, but government officials said that while they studied that project, they believed that their plan differed in ambition and scope.

Few argue with the need for such programs and alternatives to crime for young people. But security analysts faulted Mr. Calderón for not attacking corruption by building effective, accountable local and state police and judicial institutions, a herculean task that Mr. Peña Nieto so far has not shown much sign of taking on either.

“I do not see anything in his nearly first three months that show he is taking on impunity,” said Edgardo Buscaglia, a scholar of organized crime at Columbia University who has long studied Mexico and advised international panels.

Animal Politico, the political Web site, went as far as to post a discussion last week on whether Acapulco is lost and Guerrero a failed state, with most comments pointing to chronically weak institutions there that the administration has yet to address.

“The authorities should attack the root of the problem: the lack of efficient response from the institutions for security, investigation and imparting justice,” said Carlos Heredia Zubieta, the director of international studies at the Center for Research and Teaching in Economics, a research group in Mexico City.

Some experts saw the rollout of the crime prevention program, with government officials’ acknowledgment that it was still a work in progress, as more of a public relations move in the middle of a wave of violence than a well-crafted plan.

“It is not a program,” said Alejandro Hope, a security analyst and former Mexican intelligence agent. “It is generic instructions launched from the stratosphere.”

Mr. Peña Nieto has made other promises to improve security, including forming a paramilitary unit to police the worst of the lawless rural areas, but he has yet to announce details.

Some of the delay no doubt stems from the fact that nominees to main security posts have yet to be ratified by the country’s Senate. On Thursday, the names of two top security officials expected to be involved in forming the new unit were formally submitted to the body.

American officials have so far hung back, giving the new president time to get his team in place before assessing how well they will work together. Representatives of Mr. Peña Nieto said they were in talks with American officials to discuss using some of the $1.9 billion in the Mérida Initiative, Washington’s signature antidrug plan for crime prevention in Central America. The United States Embassy said in a statement Friday that it already supported crime prevention programs, but that it was continuing to discuss Mérida financing with the new government.

Guerrero presents a microcosm of the nation’s problems as whole. There is the typical drug trafficking, as the state is crossed by traditional transport routes for cocaine from South America, and its mountainous terrain allows for plenty of hiding spots for marijuana and poppy production. But there are also many local gangs active in drug dealing, extortion, kidnapping and robbery in and around Acapulco, and as residents tell it, they are seeping into smaller villages as well.

“Part of the problem here is that there are different types of violence going on, and each require a different sort of response,” said Chris Kyle, a University of Alabama anthropologist who has studied Guerrero’s violence. “There’s probably been a decline in the violence associated with drug trafficking, which is the part of the equation most amenable to a federal solution. The street hooliganism and small kidnapping-extortion rackets are better addressed by local police forces, and these are ineffectual in Guerrero.”