An urgent manhunt is under way after three young boys were abducted from a foster home in south London by their father, who was armed with a knife.

Scotland Yard are searching for Imran Safi, 26, who is said to have threatened their foster carer at knife point and used force to take the brothers, who have not been seen since.

Bilal, Mohammed Ebrar and Mohammed Yaseen Safi – aged six, five and three – were snatched from the garden of the Coulsdon house last Thursday.

It is understood that the boys were shortly due to be formally adopted by a new family, which detectives believe could be a motivation for the abduction.

The three brothers were playing in the garden while their foster carer was inside the house on Coulsdon Road at around 6pm on August 20.

The foster mother heard footsteps and became aware of Safi, who she said was armed with a knife and threatened her before forcibly taking the boys and driving off.

She did not suffer any serious physical injuries in the incident but is “understandably distressed”, police said.

More than 100 officers are involved in the operation to locate the children and it is believed that Safi, who lived in the local area, received assistance from others.

Eight people – relatives and friends of Safi – have been arrested on suspicion of involvement in the abduction of the three boys and were bailed to a later date.

It is not yet known if the children’s father, who is an Afghani national and has links to Pakistan, has travelled overseas.

Although he was not said to have access to their passports, police believe it is possible the children have been abroad due to a lack of sightings since their disappearance.

Detectives are working with national and international agencies to identify any travel to a foreign country and an all-ports alert was issued shortly after they were taken.

Scotland Yard is appealing for information regarding the movements of a red Nissan Qashqai car, registration PK13 WFO, throughout last Thursday afternoon in the Croydon area.

Anyone with a dashcam who may have noticed a vehicle of that description is urged to check their footage, and anyone else who spotted the car in the local area should contact police.

It is not believed that there is an immediate risk to the children’s physical safety, but detectives are growing “increasingly concerned” about their wellbeing.

Commander Jon Savell, said: “Our absolute priority at this moment in time is the welfare of these three children.

“They have been taken from a place of safety and we are growing increasingly concerned about their wellbeing, particularly as we remain in the midst of a global health crisis.

“While we do not believe at this time there is any immediate risk to their physical safety, their location, access to accommodation, healthcare, and other provisions is entirely unknown.

“More than 100 officers are currently working to locate and bring these children home safely.”

Chief Superintendent Dave Stringer, commander of the South Area Basic Command Unit, said: “This incident involved the use of a weapon and violence and we are incredibly concerned for these three young, vulnerable children who are now being hidden by an individual who may be armed with a knife.

“We know there are people with detailed knowledge of the whereabouts of these children, and we fully appreciate there may be very good reasons for those individuals not wanting to come forward.

“But right now I would strongly urge them to do the right thing and assist us in locating them.”

Anyone who may have information regarding the red Nissan Qashqai car, or believes they have seen Safi and his children since August 20, is asked to contact detectives immediately on 07942599374.