* Obama gives Calderon's crackdown vote of confidence

* Mexican army accused of rights abuses in drug war

* Calderon says he's committed to protecting human rights

GUADALAJARA, Mexico, Aug 10 (Reuters) - U.S. President Barack Obama said on Monday that drug cartels are Mexico's main human rights abusers and not the army, which has come under criticism for heavy-handed treatment in a drug war.

President Felipe Calderon has come under fire for using the Mexican army to police states plagued by drug violence, as rights groups have reported random arrests, torture and a few cases of civilians being shot.

Concern about abuses by soldiers could hold up millions of dollars in U.S. equipment pledged as aid for Mexico's drug war, but Mexico insists any violations are isolated incidents.

Obama, in Mexico for talks with Calderon and Canadian Prime Minister Stephen Harper, defended Mexico's army crackdown.

"The biggest by far violators of human rights right now are the cartels themselves that are kidnapping people, extorting people and encouraging corruption. That's what needs to be stopped," Obama told a news conference in the western city of Guadalajara.

"I have great confidence in President Calderon's administration applying the law enforcement techniques that are necessary to curb the power of the cartels but doing so in a way that's consistent with human rights," Obama said.

Since coming to power in December 2006 Calderon has deployed thousands of troops to fight drug smugglers. The onslaught has failed to curb cartel violence, with about 4,000 people killed this year, most of them rival drug smugglers or police.

Mexico's human rights commission has documented cases of the army arbitrarily detaining drug suspects, beating them or torturing them with electric shocks.

Soldiers suspected of abuse are tried in military courts, which tend to be too lenient on violations like rape or murder, Human Rights Watch says.

U.S. Senator Patrick Leahy, a Democrat and chairman of a subcommittee that oversees foreign aid spending, has said Mexico has not met human rights requirements for the release of 15 percent of a $1.4 billion drug aid package agreed in 2007.

Mexico, which is working to train its police and improve coordination with the army, insists there is no problem.

Calderon said his government was committed to human rights and noted his drug war was about people's right to security.

"In every case there has been a scrupulous effort to protect human rights," he told the same news conference.

"Anyone suggesting the contrary should prove a case, one single case, where the authority did not act, where it violated human rights or the authorities did not punish whoever abused their legal power," he said.