Mexico City - Mexican authorities confirmed Friday the deaths of 16 people due to swine influenza over the past three weeks, while a further 45 deaths were suspected from the disease.

The situation is so dire that Mexico City has closed its schools and President Felipe Calderon cancelled a visit to the northern city of Ciudad Juarez.

"The cases we have proved (of deaths) due to this virus are these 16, and we are awaiting confirmation of the rest," Mexican Health Minister Jose Angel Cordova Villalobos said.

He spoke of a "controlled epidemic," in which a further 943 people have been hospitalized.

"We had confirmation that it was not the usual seasonal influenza virus," he noted.

On Mexico's northern border, California and Texas have reported seven cases of swine flu, but no deaths as of yet, US federal health officials said Thursday.

US officials said there was no evidence the people had been in direct contact with pigs, meaning an unusual strain of the respiratory infection is spreading from person to person, the Washington Post reported Friday.

Late Thursday, Cordova Villalobos announced - in a message broadcast by all major radio and television stations - the suspension of school lessons in Mexico City and its metropolitan area, where most of the cases have been located.

The capital and the adjoining state of Mexico hold over 20 per cent of the country's population of 105 million.

Cordova Villalobos said the swine flu virus is "a mutant of a virus that comes from pigs, that had already been described in 1976."

Mexican authorities sent 17 samples to Canada, and received confirmation that 16 of those presented swine flu.

Symptoms of the illness include very high sudden fever, headaches, red eyes, nasal flow and coughing. It was said to be highly contagious.

The minister noted that lessons would "very probably" be suspended for several days.

"What we need to avoid is for it to get complicated," Cordova Villalobos said.

The authorities did not know whether the flu vaccine that is normally given to those members of the population that are regarded as being particularly at risk has protected those people from the new virus.(dpa)