Bogota  - Colombian President Alvaro Uribe, who just returned from a regional summit in Argentina, has come down with swine flu, his office said Sunday in Bogota.

All participants in the Union of South American Nations (UNASUR) summit, including the other presidents, were exposed to the illness "through diplomatic channels" and were warned to watch for symptoms of the A(H1N1) virus, Uribe's office said.

There was no word yet on whether other regional leaders had been infected.

Shortly after his return from the summit on Friday, Uribe came down with a headache and fever. He was responding well to medication, spokesman Cesar Mauricio Velasquez said.

Costa Rican President Oscar Arias returned to work earlier this month after being quarantined for seven days with a mild case of the swine flu.

In Colombia, there have been 621 confirmed cases of the virus and 29 deaths. (dpa)