Scores of children were left with nowhere to go Thursday night as French riot police gathered outside a refugee camp in Calais. Officials had pledged to close the camp, known as “The Jungle,” and resettle all of remaining migrants. But aid workers said hundreds of unaccompanied children remained unregistered and, with the camp closing, some faced possibly sleeping outdoors for a second night in a row. “The UK and French governments promised to keep children safe throughout the demolition,” UNICEF (the United Nations Children’s Fund) said in a statement, warning against human traffickers. “Yet right now, the situation for some children in Calais is more dangerous than ever.” According to the French Interior Ministry, the UK had agreed to transfer 274 unaccompanied minors from Calais. The French government, which has taken the lead in dismantling the camp that became the symbol of Europe’s failure to handle the refugee crisis, urged the UK to “quickly take responsibility.” The UK should “welcome these minors who wished to be transferred to the UK,” the ministry said in a statement. “This is the best way for them to be protected.” But as of Thursday afternoon, the children appeared to be in limbo, with a group of about 100 minors gathered outside the camp, uncertain about whether they would be helped or arrested, CNN’s Melissa Bell reported. Aid groups said they were told to bring the children – who say they have been trying for days to register without success – outside the camp entrance, where buses would come to take them to a registration site. No buses had come, they said. Human Rights Watch: France has failed children in Calais Bell said there had been no violence as yet between police and migrants, but anxiety was growing among the unaccompanied teenagers, many of them from Afghanistan, about what might happen. Children face arrest Inca Sorrell, of the NGO Help Refugees, told CNN that authorities had said children who were not registered by 2 p.m. local time (8 a.m. ET) Thursday would face arrest – but that there had been no information from the officials in charge of the registration process. “There’s no one here to register these children, so we have no idea – it’s just waiting and making sure they are okay.” She said she had already seen police that morning arrest four children with wristbands showing they had registered. The Calais prefecture told CNN that no one had been arrested by Thursday lunchtime but that if a migrant at the camp refused to leave, the border police would intervene, ask for the person’s papers and place them in “administrative custody.” Those whose papers are not in order risk being sent home. “What is going to happen for those who do not want to leave is that we will give them two solutions: either they join a shelter, or else they will have to leave Calais and be faced with the French law,” the prefecture said. Officials told CNN they had processed and found shelter for about 6,000 migrants. “This really is the end of the Jungle … Our mission is accomplished and it is now time for the migrants to start a new chapter as they begin a new life,” Calais prefect Fabienne Buccio said Wednesday. She had earlier vowed that the camp would shut down that night “no matter what.” Muhammad, a 16-year-old Egyptian migrant, told CNN he had slept rough because he wasn’t registered by the authorities, a process that would have allowed him to sleep inside shipping containers at the site. He said he had slept on the ground just in front of the containers, with some 20 to 30 other minors. The British Red Cross urged the French authorities to ensure that no child spent another night outside. Gloria Micallef, of the NGO Care4Calais, told CNN Thursday morning that some children had stayed in some of The Jungle’s remaining structures overnight but others had slept on a pile of rubbish, too scared of the fires to sleep in a confined space. They ranged in age from 13 to 17 years, she said. Lives in danger “These children have escaped from terrible situations and they’ve come to Europe with the hopes of having a better life, and yet we are endangering their lives once again,” she said. French immigration officials have been carrying out the registration process but aid workers have criticized a lack of organization, saying extremely long lines had prevented many children getting registered since the process began Monday. Micallef said that at 1 p.m. Wednesday police had turned children away back into The Jungle, saying there was no more space. “We were hoping that this morning we could get the children registered but apparently there is no registration for children right now,” Micallef said. Dorothy Sang, a Save the Children representative at the Calais camp, said it was still not clear Thursday afternoon what those unaccompanied children who had not been registered were supposed to do. The UK government has committed to take unaccompanied children from The Jungle who have family ties in Britain, as well as considering the cases of other unaccompanied minors without family connections. But that process only got under way in the past week. Asked Thursday about reports that migrants, in particular young people, were still sleeping rough in The Jungle, the Calais prefecture’s office said these were migrants who had only arrived in the area Wednesday and so were not included in the original resettlement plan. As for claims of unaccompanied minors still seeking shelter in the Jungle, the prefecture’s office told CNN that these young people had refused to get on a bus to a nearby shelter. “Right now we are cleaning up the camp and by Monday The Jungle of Calais will no longer exist. We have fulfilled our mission. The operation is finished,” the prefecture’s office said. French officials said up to 7,000 people were living at the camp Monday before evacuations began. However, NGOs told CNN the figure was closer to 10,000. In a statement Wednesday, Interior Minister Bernard Cazeneuve said that 5,596 migrants in total had been taken elsewhere since the operation to dismantle the camp began, including 234 unaccompanied children sent to the United Kingdom. On Wednesday, he said, 1,215 adults had left the camp on board 32 buses, bound for centers across 11 regions, while 133 children had been directed to provisional shelters.