Four men have been arrested as police continue to search for a father accused of abducting three young boys from their foster home in south London.
The Met launched an urgent appeal seven days after the boys, aged six, five and three, were reported missing.
All four men arrested, aged between 21 and 41, are said to know Mr Safi.
Detectives said all of the men were arrested in Ilford in the early hours of Friday on suspicion of being involved in the abduction of the three brothers.
The Met said all four remain at a police station in south London for questioning.
Ch Supt Dave Stringer said the latest four arrests brought police “one step closer” to finding Mr Safi.
“Since we appealed for help yesterday afternoon we have received just over 30 calls from members of the public,” he said.
“I would really urge anyone from the Croydon, and now Ilford, area to think long and hard about if they saw these children, or their father, the evening of Thursday, 20 August and possibly the morning of Friday, 21 August.”
Eight other people aged between 17 and 37 and based in Croydon have previously been arrested in connection with the abduction in the week since the alarm was raised and have been bailed to a later date.
An image of Mr Safi has been circulated to all ports and borders amid concerns he may attempt to take the boys abroad.
All three brothers were playing in the garden while their foster carer was inside the house on Coulsdon Road when they were taken, detectives said.
The foster carer, who told officers that Safi threatened her with a knife, did not suffer any serious physical injuries but was “understandably distressed”.