The United States has put 12,000 medical personnel on alert for conducting relief effort in the quake-torn Haiti, Health and Human Services Secretary Kathleen Sebelius said Thursday.

"We have 12,000 medical personnel on alert. Three-hundred of them are on their way today," Sebelius told MSNBC, adding that US Centers for Disease Control and Prevention will also dispatch experts to Haiti for monitoring the spread of disease.

Tens of thousands people have been feared dead in a 7.3 magnitude earthquake, which struck Haiti on Tuesday afternoon. International Federation of the Red Cross estimated that some 3 million people may have been affected by the earthquake.

"Doctors nurses, paramedics, emergency medical technicians, and the other medical personnel in our National Disaster Medical System and US public Health Service are preparing to travel to Haiti to provide immediate medical care to the injured," said the secretary in a statement Wednesday on the deadly earthquake.

"Our on-the-ground medical teams will be traveling with medicine, medical supplies, and equipment to help save lives during the critical post-earthquake timeframe," said Sebelius.

(Xinhua News Agency January 15, 2010)