Mexico's navy has seized more than a tonne of cocaine stuffed inside frozen sharks.

Officers cut open more than 20 shark carcasses filled with slabs of the drug after checking a container ship in the southern Mexican state of Yucatan.

Drug gangs are coming up with increasingly creative ways of getting drugs into the United States - in sealed beer cans, religious statues and furniture - as Mexico's military cracks down on the cartels moving South American narcotics north.

President Felipe Calderon has sent 45,000 troops and federal police across Mexico to try to crush powerful smuggling cartels.

But traffickers armed with arsenals of grenades and automatic weapons are far from defeated, and violence has spilled over into US states like Arizona.

Some 2,750 people have died in drug violence in Mexico this year, a pace similar to that of 2008, when 6,300 were killed.

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