GENEVA, SWITZERLAND - The number of global swine flu deaths spiked by 700 in a week, the World Health Organisation said Friday, as Ukraine closed schools and cinemas in the toughest measures taken in Europe over the virus.

More than 5,700 people have now died from the A(H1N1) since it broke out in April in Mexico and the United States in April, the WHO said.

The biggest rise in the past week was recorded in the Americas, were 636 more people were reported killed by swine flu, bringing the region's death toll to 4,175, the UN agency said.

Fatal cases in Europe also climbed to at least 281, while those in Asia-Pacific rose to 1,070.

"In the temperate zone of the northern hemisphere, influenza transmission continues to intensify, marking an unusually early start to winter influenza season in some countries," said the WHO.

Ukraine confirmed its first swine flu deaths, prompting Prime Minister Yulia Tymoshenko to order schools and cinemas closed and ban public gatherings for three weeks to contain the spread of the virus.

The government will also introduce "special regimes" to limit the movement of Ukraine's citizens from one region to another for non-urgent purposes, she said. Ukraine has borders with four EU countries.

The prime minister's tough actions came as Ukraine confirmed four deats from the A(H1N1) virus, amid a growing panic over several dozen unexplained deaths in the west of the country.

"We can say today that Ukraine has entered into the zone of the swine flu epidemic," Health Minister Vassyl Kniazevich said.

In the United States, the virus may have infected up to 5.7 million over the first four months of the outbreak, according to a study by the government's Centers for Disease Control and Prevention (CDC).

The figure is more than 100 times the number of cases confirmed in laboratories.

The researchers estimated that between 1.8 million to 5.7 million cases of A(H1N1) flu occurred in the United States in the four months from April, when the virus was first reported.

Of those cases, between 9,000 and 21,000 were hospitalised, the study said.

"We have been saying that we were just finding the tip of the iceberg with our laboratory confirmed reporting," Anne Schuchat, the director of the national center for immunisation and respiratory diseases, told reporters.

The A(H1N1) virus has also spread in European football leagues, just days after the French first division clash between Paris Saint-Germain and Marseille was postponed after three Parisian players were diagnosed with swine flu.

Spanish second division team Real Betis, based in Sevilla, has requested that its game on Sunday be postponed after 13 players became sick with swine flu.

The virus has also made its way into the English Premiership where Blackburn Rovers and Bolton reported that players and staff had contracted it.

Countries in the northern hemisphere have been arming themselves with swine flu vaccines for the winter months.

The WHO said experts concluded after a meeting this week that a single dose of swine flu vaccine would provide sufficient immunity against A(H1N1).

These vaccines were found to be safe for usage by pregnant women and can also be administered alongside seasonal flu vaccines, according to conclusions drawn from the meeting.

While clinical data was limited on the effects of vaccination on children under the age of 10, the WHO said countries should give a single dose to as many children as possible rather than vaccinating only half of the young population with two shots each.