MEXICO CITY, Mexico (AP) – Cuba suspended flights to and from Mexico yesterday, becoming the first country to impose a travel ban, as the fast-moving swine flu strain extended its reach overseas and in the United States.

World health officials in Geneva said they believed the virus appears to be establishing itself in communities and be able to produce larger outbreaks outside Mexico.

“It’s a very serious possibility, but it is still too early to say that this is inevitable,” the World Health Organisation’s flu chief, Dr Keiji Fukuda, told a telephone news conference.

The global health body insisted that travel restrictions were ineffective, but Cuba’s 48-hour suspension came as the EU’s disease control agency as well as Canada, Israel and France warned against non-essential travel to Mexico.

“Border controls do not work. Travel restrictions do not work,” WHO spokesman Gregory Hartl said, recalling the 2003 SARS epidemic that killed 774 people, mostly in Asia, and slowed the global economy.

“There was much more economic disruption caused by these measures than there was public health benefit,” he said, adding that WHO is advising countries to provide treatment for the sick and make sure national plans are in place to ease the effects of a larger outbreak.

Mexico City closed gyms, swimming pools and pool halls yesterday, and ordered restaurants to limit service to takeout – extending a growing shutdown that already included schools, state-run theatres and other public places.

But the swine flu has already spread to at least six countries besides Mexico, prompting WHO to raise its alert level on Monday but not call for travel bans or border closings.

WHO raised the alert level to Phase four, meaning there is sustained human-to-human transmission causing outbreaks in at least one country. WHO’s pandemic alert system was revised after bird flu in Asia began to spread in 2004. Monday was the first time it has ever been raised above Phase three.

Fukuda cited a New York City case in which some students were infected with the virus, but did not travel like some of their infected classmates to Mexico, where most of the people confirmed with the virus were stricken. He said health experts were examining the situation.

WHO calls this “community transmission” and says it’s a key test for gauging whether the spread of the virus has reached pandemic proportions.