At least 36 people were arrested - the youngest a 12-year-old - in a night of violence on the streets of Hong Kong that saw police officers pull pistols on the crowd.

Protesters threw Molotov cocktails and security forces responded with tear gas and water cannon as the anti-government demonstrations that began in June escalated. In a statement, Hong Kong police said that 15 officers were hospitalised, by a "large group of extremely violent protesters."

In a statement, the police also confirmed that six officers pulled their weapons on the crowd while one "fired a warning shot into the sky". It said that petrol bombs and bricks were thrown after a hardcore of set up barricades in Tsuen Wan.

Hong Kong police met violent resistance on the streets of Tsuen Wan.

The police "severely condemn[ed] such violence which was outrageous and have overstepped the bottom line of a civilised society."

The protests began in Hong Kong in June over legislation that would have allowed extradition from Hong Kong to China. But the demonstrations have broadened into pro-democracy movement, with many more protests planned in the coming weeks and months.

On Wednesday, a rally is planned at the headquarters of Cathay Pacific Airlines, the Hong Kong firm that was ordered by China to dismiss staff that took part in the protests.