UPDATE: Police have arrested two men in relation to this incident, statement below...
Police say they are "extremely concerned" for a 17-year-old boy who failed to return home after a night out.
Adam Pickup was on a night out in Manchester city centre with friends when he left Fab Cafe in Portland Street at around 3.20am on Saturday.
The teenager from Stockport was last seen on CCTV walking along Oxford Street at about 3.30am, where he appeared to be speaking with a man and woman.
On Sunday evening, a Greater Manchester Police (GMP) spokeswoman said: "Police have arrested two men as part of their inquiries to locate the missing man Adam Pickup.
"They are currently in police custody for questioning. Inquiries are ongoing to find Adam and police continue to appeal to anyone who may have seen him or knows of his whereabouts."
GMP are appealing for the public's help to trace Adam and have urged the man and woman to contact them.
Superintendent John Berry said: "We are extremely concerned for Adam's welfare and we are stepping up our searches.
"If you have any information about his whereabouts or you remember seeing Adam we would urge you to get in touch and tell us where you saw him or where he may have been going.
"In particular, while he was walking up Oxford Street Adam appears to be walking alongside a couple and speaking to them.
"If this was you please get in touch and tell us what you know. We are trying to trace Adam's movements and at this point it is not clear what direction he goes in. This couple may have vital information to help us find him."
Adam is described as white, 6ft 2in tall, slim with mousey brown hair. He was wearing a maroon long-sleeved collared shirt, black jeans and black leather Nike trainers with white soles.
The man and woman are described as being white, both with dark hair and wearing dark clothing. The man appears to be wearing glasses and a blue scarf.
Anyone with information about Adam's movements or whereabouts should contact police on 0161 856 9675, or the independent charity Crimestoppers, anonymously, on 0800 555 111.