Police used tear gas and truncheons to try to disperse hundreds of people who had gathered in support of President Rodrigo Duterte's recent comments that he wanted to loosen his nation's alliance with the United States.
A total of 23 protesters were arrested, said Chief Inspector Arsenio Riparip, one of the officers overseeing the incident.
He said the protesters broke through the line of police securing the embassy's gates.
"We had to disperse them. They started it. They were trying to enter the embassy," Riparip told AFP.
"We had to use tear gas. They overpowered our policemen."
A police van reversed quickly back into a crowd of dozens of protesters and then forward, running over at least two people and banging into others, footage broadcast by local television network ABS CBN showed.
Photos showed a grey-haired man afterwards trapped underneath the stationary van, with his leg and hips under one of the back tyres.
Manila police chief Oscar Albayalde confirmed the police van hit protesters but insisted the driver was not at fault.
"They weren't really run over," Albayalde said in a statement, referring to the protesters.
"The rallyists were trying to flip over the patrol car. In the process, the driver extricated the patrol car and inadvertently hit some unruly protesters who sustained minor injuries."The rally came as President Rodrigo Duterte visits Beijing to strengthen relations with the world's second-largest economy amid deteriorating ties with former colonial power the United States, sparked by his controversial war on illegal drugs.
Policemen block protesters during a rally in front of the US embassy in Manila on October 19, 2016. Source: Getty
At least 10 people were taken to hospital after being hit by the police van, Renato Reyes, secretary general of left-wing activist group Bayan (Nation), told reporters.
The protesters were calling for the removal of US troops in the southern island of Mindanao.
"There was absolutely no justification (for the police violence)," Reyes said. "Even as the president avowed an independent foreign policy, Philippine police forces still act as running dogs of the US."
One of the protest leaders, Amirah Lidasan, accused the police of starting the violence.
"It was the police who attacked the protesters. First they rammed the police vehicle against the people. Then they released tear gas and hit us with truncheons," she said.While the Philippines is a defence ally of the United States, Duterte -- elected president in May on a ruthless anti-crime platform -- has said he wants to distance the country from America.
A fireman trains his hose at surging protesters as they force their way towards the US Embassy in Manila, Philippines, Oct. 19, 2016. Source: AAP
He has launched abusive tirades against US President Barack Obama and warned he may eventually cut ties altogether, after the US government raised alarm over thousands of people killed in Duterte's anti-drug campaign.