[Above: Mexican President Felipe Calderon meets with US Secretary of State Hillary Clinton at Los Pinos Presidential Palace in Mexico City, Mexico on January 24, 2011.]

GUANAJUATO, Mexico - US Secretary of State Hillary Clinton gave President Felipe Calderon's controversial crackdown on drug gangs firm support Monday in Mexico, saying it was "absolutely necessary."

More than 34,600 people have died in spiraling violence since Calderon deployed tens of thousands of soldiers to take on organized crime in 2006, amid growing allegations of military abuses under the crackdown.

"What President Calderon has done is absolutely necessary," Clinton said at a news conference in the colonial city of Guanajuato with Mexican Foreign Secretary Patricia Espinosa.

"There is no alternative," she added. "The drug traffickers are not going to give up without a terrible fight."

Clinton admitted the Calderon administration still faced challenges on investigating human rights abuses and reforming the justice system, but hailed "progress" by the Mexican government on those matters as well.

Clinton met with Espinosa in Guanajuato on a one-day mission aimed at improving collaboration between the closely-tied neighbors.

The two top diplomats discussed competitiveness as both countries emerge from the financial crisis, development along their 3,000-kilometer border and advancing the global climate change agenda after the Cancun Summit last December.

"Our relationship is stronger than the current political challenges which may get in the way," Espinosa said.

Clinton was due to meet with Calderon in Mexico City before returning to Washington.

Despite the arrests and killings of a string of gang leaders and major drugs hauls in recent years, violent attacks continue to hit the headlines.

At least 30 people were killed in a 24-hour period since Sunday in northern Mexico, including seven players gunned down at a soccer match in Ciudad Juarez near the US border.

A weekend car bomb separately killed a police officer in central Mexico, and three teenagers were injured by a grenade found in the northern city of Monterrey.

Joint US and Mexican efforts to combat the violence have increased in recent years, but tensions rose with the release of classified memos by WikiLeaks that showed US diplomats expressing concern about the Mexican army's ability to win its war on drugs.

New cables were released Sunday by Spanish newspaper El Pais, demonstrating US fears over the porosity of its southern border.

They also showed US-Mexico collaboration on the politically sensitive topic of immigration, including Mexican authorization for US officials to question undocumented migrants in Mexico.

The United States - the main market for Mexico-trafficked drugs and the top supplier of illegal weapons to Mexico - has promised training and equipment to Mexico's security forces under a three-year, $1.3-billion Merida Initiative to tackle organized crime, which is set to expand this year.

Drug violence left 15,273 dead in Mexico in 2010, according to official figures, making it the deadliest year yet since Calderon launched his military campaign.

Human Rights Watch slammed what it called "serious abuses" allegedly carried out by Mexican security forces.

"Yet those responsible are virtually never held accountable," the New York-based watchdog said in its annual report.