Teens allegedly assault NSW police officer

Steve Zemek

Three teenagers have been charged after a senior police officer was allegedly assaulted and mugged on Sydney's northern beaches.

Four teens aged 16 and 17 were initially arrested and taken to Manly Police Station following the alleged incident at a Warriewood fast food restaurant on Friday night.

Police were called to the McDonald's after reports of a large group causing a disturbance inside.

After they ushered the group outside, police allege a chief inspector, who was attempting to move on five teenagers, was knocked to the ground and had his mobile phone and badge stolen.

"He was ... viciously attacked, he was thrown to the ground, his shirt was ripped," Assistant Commissioner Mark Jones told reporters on Saturday.

Police say the group fled on foot. However, four of them were arrested in the early hours of Saturday morning.

One of the 17-year-olds was ultimately released pending further investigation, while the three remaining teenagers were charged with a range of offences including affray and resisting or hindering a police officer.

The two younger boys were also charged with assaulting a police officer without actual bodily harm.

They have all been refused bail ahead of a scheduled appearance in a children's court on Sunday.