(Updates with name of immigration official, details)

MEXICO CITY, Oct 27 (Reuters) - Mexico has arrested two top anti-drug officials accused of taking bribes of up to $450,000 a month to leak intelligence to a drug trafficking cartel, the attorney general's office said on Monday.

The two men received between $150,000 and $450,000 a month for informing the Beltran Leyva drug gang about police operations, including safe house raids and arrest targets.

"They handed over secret information and details of operations against the Beltran Leyva criminal organization," Attorney General Eduardo Medina Mora told a news conference.

The two officials are now in prison and some 30 other members of the anti-drug unit known as SIEDO have been fired.

U.S. Customs and Border Protection also arrested on Sunday a senior Mexican immigration official on the Arizona border, accusing him of smuggling marijuana.

U.S. prosecutors charged Francisco Celaya-Carrillo with intent to possess and distribute almost 169 pounds (77 kg) of the drug, which inspectors found hidden in the spare tire and gas tank of a pickup truck he drove over the border at Lukeville.

Celaya-Carrillo admitted carrying the drugs, and told police he was to be paid $10,000 to deliver the truck to Phoenix.

President Felipe Calderon has made cleansing Mexico's notoriously corrupt police forces a priority in his fight against drug gangs smuggling narcotics to the United States.

But low wages, shoddy equipment and rising insecurity amid the drug war that has killed more than 3,725 people this year have made that task increasingly difficult.

Calderon has sent more than 40,000 troops across Mexico to fight the drug gangs but despite capturing several drug lords, narco-violence continues to spiral. (Reporting by Tomas Sarmiento in Mexico City and Tim Gaynor in Phoenix; Editing by Eric Beech)

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