Police commissioner Michael DeSilva said an altercation between protesters and police was unfortunate, but maintained that protesters were acting unlawfully.

“It is regrettable that this incident has occurred without a doubt,” he said. “However it is clear to us that there were those among the protesters that were determined to confront the police acting in a lawful execution of their duties.” Officers reportedly deployed pepper-spray and Tasers during an altercation early yesterday afternoon, with officers attempting to move protesters who had surrounded the House of Assembly grounds in protest of controversial airport plans.

Speaking at a press conference yesterday afternoon, Mr DeSilva said that police were already at the House when the first protesters arrived, and had warned them to abide by lawful instructions.

“Throughout the morning, in an attempt to allow access to the House of Assembly, officers engaged with protesters continually to warn them about their conduct and to encourage them to desist from obstructing the entrance to the grounds or building,” he said.

“Once the Speaker of the House declared the House would sit today, police initiated positive action to open a path to the House. They approached the protesters who were blocking access, warned them they were committing offences, and instructed them to desist. Immediately the crowd surged and some of the protesters assaulted the officers.

“Some officers deployed incapacitant spray in a proportionate response to disperse the crowd and create a safe separation. The decision to de-escalate was taken later after the Speaker announced that the House would not sit today.”

He said it is important for the public to be aware that there is a significant difference between peaceful, lawful protest and “unlawful activities that threaten the democratic process”.

He said: “We respect and uphold the constitutional right to freedom of speech, to gather and to peacefully protest, but we remind the protesters and organisers that their actions must be lawful and they must not intrude on the rights of others or impede on the rule of law.

“Our investigators are reviewing video footage that was captured today to identify offenders with a view to produce files for the Department of Public Prosecution to review. We received one complaint from a member of the public against a police officer, and that matter will also be investigated.”

Asked who ordered riot police to intervene, he said it was not the Premier, the Speaker of the House or the Governor.

“The only people that can instruct police officers to use lawful force is police officers,” he said. He later added: “Whenever we use force, it’s after trying every other option we can think of. Police officers don’t walk into a situation and pull out Tasers and batons and incapacitant spray.”

Police also revealed that one protester was arrested on suspicion of assaulting an officer with a stick, but the service determined that other offenders would be dealt with by way of summons.

Asked what offences the protesters were allegedly committing, Mr DeSilva said: “The general offence was obstruction. It is an offence under the Summary Offences Act to obstruct lawful duty, lawful business. People moving along the street.

“You can’t block other people from doing what they are allowed to do.” The commissioner confirmed that officers at the scene were using body cameras at the time of the incident, and that the footage would form the basis of their investigations, but said the footage would not be released publicly for legal reasons.