MEXICO CITY: Mexico was approved for three billion dollars in international loans to fight the swine flu crisis, as the country began a five-day shutdown Friday to try to halt the spread of the virus.

As nations worldwide stepped up safety measures following a World Health Organization (WHO) warning that a global pandemic may be imminent, Mexican officials said the rapid course of the H1N1 virus could be slowing.

They said 12 people were confirmed dead and 300 people were infected with the virus, a new flu strain that combines bird, swine and human influenza, but Health Minister Jose Angel Cordova was hopeful the worst might be over.

"The increase in the number of dead does not mean that more people have died in the past few hours, but that we have carried out more examinations," Cordova said.

In Washington, the Inter-American Development Bank said it would approve three billion dollars in loans for Mexico, the epicentre of the latest outbreak, which was already struggling from the global financial crisis.

Mexican authorities meanwhile cancelled the traditional gatherings of workers to celebrate May Day, as the country went into a five-day holiday they hoped would minimise public contact and slow the viral spread down even more.

Restaurants, bars, tourist sites and other public venues remained closed in the capital, Mexico City, and elsewhere.

"Stay at home with your family," President Felipe Calderon said in an address to the nation, which is officially on holiday until Tuesday.

All the confirmed deaths from the swine flu virus have occurred in Mexico except one, a Mexican toddler who died across the border in the United States.

US health officials said the number of infections there had hit 118, while a number of other nations -- including Britain, Japan, South Korea and New Zealand -- reported new H1N1 cases.

Most cases have involved only mild symptoms of the illness that can be easily treated with existing flu medicines, and some experts have suggested that the virus may have weakened as it was carried outside Mexico.

The WHO said it would not as yet invoke the highest health threat level -- what it calls phase six, meaning a worldwide pandemic is under way -- but kept it at phase five, indicating a pandemic is imminent.

The WHO's acting assistant director Keiji Fukuda said the virus was behaving like a typical influenza virus, meaning there could be an increase in cases in the southern hemisphere, which is about to enter into winter.

"This is something we have to be on the watch out very carefully for," Fukuda said.

In Britain, where three more cases were confirmed, the government's top health official Liam Donaldson tried to ease public concerns.

"To put things in proportion, in any flu, even the seasonal flu, there are some deaths, often of elderly people and the very frail," he said.

Although it was initially dubbed swine flu, the WHO is now officially referring to it as Influenza A (H1N1), in part because the virus is not spread by contact with pigs but is transmitted from person to person.

The existence of human transmission led Mexico to impose the virtual closure of public life, while across the border the White House apologised for comments by Vice President Joe Biden that set off fears about public transport.

"I would tell members of my family -- and I have -- I wouldn't go anywhere in confined places now," Biden said. "I would not be at this point, if they had another way of transportation, suggesting they ride the subway."

He also expressed concern about air travel, and White House spokesman Robert Gibbs later said: "I'm apologising to those who were unduly alarmed."

Biden's comments drew sharp criticism from air transport and tourism officials, whose industries have already been severely hit by the economic slump.

Elsewhere, however, authorities tightened travel restrictions and took other measures to keep the virus from spreading.

Singapore invoked public health orders not used since the 2003 SARS crisis, ordering anyone arriving from Mexico to be quarantined for one week, while Israel began airport health inspections for those coming from Mexico.

May tour operators and cruise companies have suspended trips to Mexico, which estimated the flu crisis could ultimately cost the country around 70 billion dollars.