Philippine police have suspended nine officers involved in the violent dispersal of protesters outside the US Embassy in Manila, during which some were rammed with a patrol van.
National Police Chief Ronald dela Rosa has ordered an investigation into Wednesday's incident in which police officers also used tear gas in an attempt to break up a crowd of about 1000 people.
"I am angry and sad. I saw people get hurt. I don't want Filipinos getting hurt but I cannot let emotions get the best of me," dela Rosa said on Thursday.
"An investigation and full review is underway and necessary sanctions will be levied on any personnel guilty of putting lives at risk," he added.
Demonstrators marched to the embassy in support of President Rodrigo Duterte's new foreign policy which is attempting to decrease dependence on US assistance.
A police van, which had been surrounded by protesters, drove at the crowd, hitting several people, a video showed.
Protesters also threw red paint at the embassy's gate and vandalised the compound's walls with slogans reading, "US troops out!" and "US, a plague to workers."
Twenty-five protestors and 30 police officers were injured in the incident and 21 protesters were briefly detained, said capital region chief of police, Oscar Albayalde.