A major search to find missing teenager Liam Smith is continuing three weeks on from his disappearance.

Detectives are combing areas near Crathes Castle, Aberdeenshire, where the 16-year-old is thought to have got off a bus from Aberdeen on Saturday, November 17.

Liam was last seen on CCTV at Union Square shopping centre in Aberdeen at around 1.15pm shortly before boarding the 202 bus, which was heading towards Banchory.

A police spokesperson said: "The public's support and assistance has been unprecedented and I know that Liam's family are very grateful for this, as are we.

"It will be three weeks on Saturday since the 16-year-old was last seen I would like to highlight that although we may not post regular updates for the public, police searches are very much ongoing and we are supported by specialist resource which this week has included Braemar Mountain Rescue Team.

"We continue to keep in contact with Liam's family and provide them with regular updates.

"If anyone recalls seeing Liam on the day he was last seen or since then, and they haven't already spoken to Police, I would ask that they contact us on 101."

Following information received by another passenger, officers believe he got off the bus at Crathes and a sighting of him in the Crathes Estate area that afternoon has provided further information to lead their searches.

Liam is described as white, slim and 6ft 4in. He has short brown hair and walks with a distinctive gait.

When last seen he was carrying a camouflage North Face rucksack and was wearing Nike Air Max trainers.

He bought Lucozade, Jaffa Cakes and a Dairy Milk at Sainsbury's before he left Aberdeen.