The U.S. government will donate 420,000 doses of anti-viral drugs to Latin American and Caribbean nations to help them fight the A/H1N1 flu, U.S. Health and Human Services Secretary Kathleen Sebelius said on Thursday, Xinhua reported.

The donation will be distributed by the Pan-American Health Organization, represented by its Argentine director Mirta Roses, Sebelius told a WHO meeting in Mexico's southeastern resort town of Cancun.

The U.S. official also praised Mexico for its swift and aggressive response to the health crisis caused by the A/H1N1 flu, which has killed 337 people and infected 80,000 in 121 nations and regions.

WHO's Deputy Director-General Keiji Fukuda said the existing anti-viral medication remains effective in treating the  pandemic.

Health ministers and representatives from 43 nations attended the two-day meeting.