Two teenagers were subjected to a frightening ordeal when they were robbed of their mobile phones at knifepoint by a gang within minutes of each other on Saturday night in St Albans.

A police helicopter was sent to Marshalswick, where both robberies occurred, to search for the offenders.

A 15 year old boy was robbed of his phone at 9.45pm in Marshalswick Lane after he was threatened by a group of youths carrying knives.

Herts Police received a report of a second robbery, at about 10pm, of a further knifepoint robbery at The Wick, off Marshal’s Drive. A bag and mobile phone were stolen from a 17 year old boy.

Seven youths, aged between 15 and 16, were arrested on suspicion of armed robbery, and taken into police custody.

Officers also recovered a number of knives.

Inspector David Howells said that while reports of two armed robberies in quick succession would be “alarming to local residents, I would like to reassure them that we responded quickly and as a result have made arrests, and recovered items that may have been used as part of the alleged incidents.”

He has urged witnesses to either robbery, or with information that could help with the investigation to contact the police.

Phone non-emergency number 101, or Crimestoppers anonymously on 0800 555111, or online: www.crimestoppers-uk.org

Herts Police arrested:

• A 16 year old boy from Luton, who has been bailed until June 12. He was arrested at the St Albans City station, on suspicion of robbery.

• Two 15 year old boys from Luton have been bailed until June 12. They were arrested at the station, on suspicion of robbery.

• A 16 year old Luton boy who was arrested at the station on suspicion of robbery and possession of stolen property has been bailed until July 27.

• Also arrested at the station was a 16 year old boy from Luton, who has been bailed until June 12. He was arrested on suspicion of robbery and possession of stolen property.

• A 16 year old boy from Luton was arrested in Brampton Road, on suspicion of armed robbery. He was bailed until June 12.

• A 15 year old boy from St Albans has been bailed until July 27. He was arrested on suspicion of armed robbery. The location of his arrest was Brampton Road, St Albans.