Mexico City - More than a dozen armed men entered a hospital in the northern Mexican city of Chihuahua on Wednesday and abducted an alleged drug trafficker whose extradition had been requested by the United States, the authorities confirmed.

The group - made up of 12-20 men, according to the authorities - entered the hospital around 4 am and took the weapons and cellphones off seven bodyguards assigned to protect the man, Chihuahua public prosecutor's office spokesman Eduardo Esparza told German Press Agency dpa.

According to doctors quoted by the authorities, the man - identified as Crispin Borunda Cardenas - had heart problems and showed evidence of "a severe medical condition, with fatal complications in the short run." For this reason, he had been admitted to hospital a month ago.

He had been arrested in 2004, and extradition proceedings were ongoing.

"The armed group went in through the emergency area and subdued the guards, who were distributed around several areas of the hospital, until they reached the place where Borunda Cardenas was," said the Public Security Ministry.

Some 6,300 people were killed in Mexico last year in incidents linked to organized crime, and the country's authorities have deployed many thousands of military and police officers across several areas to combat the powerful drug cartels.

In the Mexican city of Juarez on the US border, 10,000 troops were maintaining martial law since last week. (dpa)