Southern Command (Southcom) chief Lt. Gen. Narciso Abaya flew to Basilan island to personally preside over the opening ceremony for the 25-room hospital in Lamitan town.
The chief of the US Special Operations command in the Pacific, Brig. Gen. Donald Wurster, was to have flown to Basilan to attend the ceremonies but was canceled.
The Philippine military had earlier said Wurster had accompanied Abaya, but clarified later that the American general canceled the trip to immediately return to his base in Hawaii via Okinawa, Japan.
A top Southcom official, however, said the cancellation was made after officials received "credible threats" against American troops in the South from Muslim Abu Sayyaf rebels. He did not elaborate.
"The US humanitarian projects in Basilan have a big impact on the lives of the people here. We are grateful to the assistance and help the US military have undertaken in Basilan," provincial spokesman Christopher Puno said.
In June 2001, Lamitan came under siege from the Muslim Abu Sayyaf rebels, who took over a Roman Catholic church and a hospital where they hid a group of hostages, including three Americans they abducted from a beach resort.
Several rebels were killed in a firefight which devastated the church and hospital, but the rebels escaped along with their hostages. Some of the hostages were freed or escaped, while others were beheaded, including Californian Guillermo Sobero.
US troops were later deployed to the southern Philippines in joint counter-terrorism operations, leading to the rescue of the last US hostage Gracia Bunrham, whose husband, Martin, died in the operation, along with Filipina nurse Edibora Yap. – With Roel Pareño