Britain has decided to take in some unaccompanied refugee children from Syria, North Africa and other conflict areas, the Home Office (interior ministry) said on Thursday, without specifying an exact number.

The British government has already pledged to receive 20,000 Syrian refugees by 2020. More than 1,000 of them – around half of them children – have already been resettled in Britain under this system, the government says.

The government had previously said that most refugee children would be better off staying in their region of origin so they can be reunited with their families; however, the Home Office said it would work with the U.N. refugee agency (UNHCR) to identify particularly vulnerable children and take them in.

“The crisis in Syria and events in the Middle East, North Africa and beyond have separated a large number of refugee children from their families,” Immigration Minister James Brokenshire said in a statement.

“… we have asked the UNHCR to identify the exceptional cases where a child’s best interests are served by resettlement to the UK and help us to bring them here,” Brokenshire added.

Aid agencies cautiously welcomed the announcement.

“The UK has a responsibility to protect vulnerable children, it is absolutely right that the government is committed to resettle unaccompanied children from conflict regions,” the U.N. children’s agency UNICEF said.

Tanya Barron, CEO of children’s charity Plan UK, said: “Any and all help for children who have been separated from their families by the war in Syria should be encouraged.

“In many cases, they are traumatised having seen their homes destroyed and loved ones killed or injured. These children urgently need help to try and rebuild their shattered lives.”

According to UNICEF, there are tens of thousands of unaccompanied refugee children, many of whom had relatives in the United Kingdom.

The agency explained that these children should be given information about their right to be reunified with their families and how to claim it.