Windows at India's High Commission in London and at the Consulate General of India in San Francisco were smashed during separate demonstrations by Sikh protesters, police in both cities said Monday.
London's Metropolitan Police force said a man was arrested Sunday afternoon on suspicion of violent disorder outside the diplomatic mission, where two security guards were slightly injured. In San Francisco, dozens of protesters gathered outside the consulate and smashed windows with their flagpoles after a skirmish with embassy workers, a protester said.
San Francisco Police Officer Robert Rueca said in an email that embassy workers were injured, though he didn't say how many or the extent of the injuries. Suspects fled and have not been arrested, he said.
The U.S. State Department was working with local authorities to investigate the incident and repair the damage.
"We certainly condemn that vandalism," White House National Security Council spokesman John Kirby said Monday during a briefing.
The protesters were affiliated with a Sikh separatist movement that seeks to create a new homeland or breakaway state, called "Khalistan."
The incidents came a day after police in India's Punjab state launched a manhunt to capture Amritpal Singh, a separatist leader who supports the Khalistan movement. His supporters staged protests in the majority Sikh state over the weekend and 112 were arrested, the Press Trust of India news agency reported.
In San Francisco, police officers arrived at the Consulate General on Sunday afternoon to find shattered glass windows. Workers described protesters trying to enter the building, Rueca said. He didn't immediately provide additional details on how the confrontation began.
On Monday morning, more than a dozen protesters were again outside the building, which was protected behind police barricades and a police vehicle in front.
Gurpreet Singh of Fresno was outside the embassy both days and said protesters planned to keep up their demands for a separate Sikh state. Singh said he arrived too late to see what happened Sunday afternoon but was told embassy workers took down the Khalistan flags protesters had put up near the entrance.
A worker then pushed a protester, cursed him and said "don't put your dirty flag here," said Veer Singh, another protester who saw the confrontation. That led protesters to begin using their flagpoles to smash in the windows, Gurpreet Singh said.
Rueca, of the police department, said protesters were blocked from entering the building.
The Consul General of India in San Francisco did not respond to an emailed inquiry for comment.
In London, footage posted on social media showed a man detach the Indian flag from a balcony of the building while a crowd of people below waving bright yellow Khalistan banners appeared to encourage him.
Police said officers were called but protesters had largely dispersed by the time they arrived.
"An investigation was launched, and one male was arrested nearby a short time later on suspicion of violent disorder. Inquiries continue," the force said.
The Indian government said it had summoned British Deputy High Commissioner Christina Scott in New Delhi to demand an explanation.
"India finds unacceptable the indifference of the U.K. government to the security of Indian diplomatic premises and personnel in the U.K.," the Indian government said in a statement.
On Monday, Punjab remained on high alert as police resumed their search for Singh, whom they accuse of inciting communal tensions.
The Khalistan movement is banned in India, where officials see it and affiliated groups as a national security threat. But the movement still has some support in the state, as well as beyond, in countries like Canada and the United Kingdom which are home to a sizable Sikh diaspora.
On Monday, at least 200 Sikh protesters affiliated with India's ruling Bharatiya Janata Party held demonstrations outside the British High Commission in New Delhi over the incident in London. The protesters, who said they were also demonstrating against the insult to the Indian flag, tried to march inside the British embassy but were stopped by police.
"Some people in the cover of Sikhism are trying to create an impression that we support Khalistan. We are against Khalistan. We don't want Khalistan," protester Arvinderpal Singh said.
U.K. Foreign Office Minister Tariq Ahmad said he was "appalled" by the violence in London.
"This is a completely unacceptable action against the integrity of the Mission and its staff," he wrote on Twitter. "The U.K. government will always take the security of the Indian High Commission seriously."
London Mayor Sadiq Khan condemned "the violent disorder and vandalism."
"There is no place in our city for this kind of behavior," he said.