Several hundred migrants remain inside the “Jungle” camp in Calais, BBC reporters at the scene say, despite French officials claiming the camp is now empty.
About 200 unaccompanied minors have been left with nowhere to sleep, our Europe reporter Gavin Lee says.
Some 30 of them have been offered housing in a warehouse, but the situation for the rest remains unclear.
They are said to be becoming increasingly desperate.
Nearly 5,600 people have been moved to reception centres since Monday, the government said in a statement (in French), including about 1,500 unaccompanied minors being housed in an on-site container camp.
Demolition crews are continuing to clear tents and shelters from the area amid smouldering fires reportedly set by departing migrants.
Fabienne Buccio, the prefect of Pas-de-Calais, said it was “mission accomplished” for the operation.
The camp has become a key symbol of Europe’s migration crisis, with its residents desperate to reach the UK.
Dorothy Sang of Save the Children earlier told the BBC that hundreds of children had not been able to register and enter the area for minors.
“When there were fires raging in the camp, the camp was cleared, but the registration process for children was closed, and the containers were full. So there was literally nowhere for children to go,” she said.
Many had run away, she added, and their whereabouts were unknown.
The UK Home Office said that French authorities were responsible for “all children in Calais during the clearance operation – including those being assessed for possible transfer to the UK”.
It was responding to a letter from Baroness Sheehan to Home Secretary Amber Rudd expressing her “extreme anger” after having seen some 100 mostly teenage boys being denied access to a processing centre on Tuesday night.
About 1,500 unaccompanied minors are being housed on-site in a temporary shelter made up of modified shipping containers, according to a charity caring for them.
Pierre Henry of France Terre d’Asile said the accommodation was full.
Unaccompanied children waiting for somewhere to sleep are becoming increasingly desperate.
Elsewhere in the camp, Afghan men walk between the embers of tents and shacks. Men and women in smaller groups are sitting and eating in the Eritrean quarter.
Two mechanical diggers are in place, operating to clear parts of the camp still alight. Riot police are surrounding the equipment telling journalists it’s forbidden to film. Many at the camp say they’re looking for new places to hide.
Some are claiming their friends are hiding in nearby forests. Others have suggested that migrants are beginning to gather elsewhere in a camp close to Lille. There’s little left of the Jungle now, but some here say they will only leave if made to do so by force.
Fires burned at the camp overnight and during the day amid the clearance work.
Aid workers have told the BBC they saw British and French activists torching shacks throughout the night.
Ms Buccio told local media it was “a tradition among the migrant population to destroy their homes before leaving”.
One man was reported to have been injured when a gas canister exploded in the flames.
More than 1,200 police officers have been deployed for the clearance operation at the camp, which is unpopular locally and has required a large security presence to prevent migrants reaching the UK on lorries or trains heading across the Channel.
Since the start of the week, French authorities have been bussing thousands of people to shelters and centres where they will be able to seek asylum.
The operation has gone faster than expected and on Wednesday afternoon Ms Buccio said: “It’s the end of the Jungle, our mission is over. There are no more migrants in the camp.”
A total of 5,596 people, including children, have been transported from the Jungle for resettlement, the French government says. This includes 234 minors brought to the UK since last week.