Manila  - Nine bank employees were killed Friday by gunshots to the head in a bank heist just outside the Philippine capital, a regional police chief said.

The suspects were inside the bank and killed the victims as they arrived for work at a Rizal Commercial Bank Corp branch in Cabuyao town in Laguna province, 35 kilometres south of Manila, Chief Superintendent Ricardo Padilla said.

One employee was critically wounded in the robbery, Padilla added.

President Gloria Macapagal Arroyo expressed shock at the killings, which drew national outrage, deputy presidential spokeswoman Lorelie Fajardo said.

"The president would like to extend her deepest sympathies for the families of all the fatalities in the gruesome and senseless killing," she said, adding that Arroyo had ordered an investigation to find the perpetrators.

"All the victims were shot in the head," Padilla said. "It appears that the victims knew the identities of the robbers. That's why they were all shot dead."

"This gruesome act is not the work of human beings," he added. "This is the work of an animal."

Padilla said investigators were still determining the amount of money taken by the robbers.

Investigators were also looking for two missing bank security guards to shed light on the killings, which were discovered by bank clients when the branch failed to open on time. (dpa)