Swine flu continued to test nerves of countries around the globe on Tuesday, with the number of confirmed cases of infection rising in the disease's origin of Mexico.

The latest report of the Mexican health department said the number of suspected swine flu deaths has risen to 159, and the number of suspected cases has increased to 2,498.

The number of confirmed human infection in the United States has risen to 64, with at least seven patients having been hospitalized, while President Barack Obama asked Congress for 1.5 billion U.S. dollars to enhance U.S. and global capacity to respond to the potential spread of swine flu.

In a letter to lawmakers, Obama asked them for a supplemental spending plan to build drug stockpiles and monitor future cases.

He said the request was made "out of an abundance of caution" in order to "enhance our nation's capability to respond to the potential spread of this outbreak."

Canada reported seven more confirmed cases of swine flu on Tuesday, bringing the total number of cases in the country to 13.

Although all the new cases are mild ones, public health officials warned of more severe cases which may result in deaths.

Spanish Health and Social Policy Minister Trinidad Jimenez confirmed on Tuesday the second case of human infection of swine flu in the country.

The patient, a 24-year-old male student from University of Valencia, had a study trip to Mexico with the person who was the first confirmed case of swine flu in Spain.

Some 30 suspected cases of swine flu are under observation in Spain, the Spanish Health Ministry said.

As of Tuesday, confirmed cases of swine flu infection have also been reported in New Zealand, Israel, Britain and Costa Rica.

In Austria, five suspected swine flu patients, all of whom had been to Mexico recently, had been quarantined and received necessary medication.

The number of suspected cases in Brazil reached 20, but the Brazilian Health Ministry reaffirmed that the swine flu virus is not spreading in the country, as no one has contracted the disease on Brazilian soil so far.

China went on full alert Tuesday to guard against the virus, as authorities ordered round-the-clock monitoring of the deadly virus and suspension of pork imports from Mexico and the United States.

Chinese President Hu Jintao Tuesday ordered the country to step up inspection and quarantine measures to prevent swine flu from entering China and ensure public health and safety.

China is hoping to get swine flu virus samples from the U.S. Center for Disease Control and Prevention to facilitate its research on virus testing.

Suspected cases of human infection were also reported in China's Hong Kong, South Korea, Denmark, Sweden, Greece, Czech Republic, Germany, Italy, Ireland, France, Poland and Holland.

Following Cuba, Argentina decided to suspend flights from Mexico as a precautious measure, and was considering requiring visitors from North America to report to the health authorities.

Since it was proved that the swine flu was not transmitted by consumption, Nicaragua suspended the restriction on imports of pork products from Mexico.

The World Health Organization said it does not recommend border closures to fight the spread of swine flu because it "doesn't work" since not all infected people show symptoms.

The European Union (EU) said it currently has no plan to impose any trade restrictions on Mexico.

"We have no plans to impose any trade restrictions at present since there is no risk from food or animal products from what we know so far," a spokesman for EU Trade Commissioner Catherine Ashton told reporters.

(Xinhua News Agency April 29, 2009)