Police have issued an urgent appeal to trace two children who have gone missing amid near-freezing temperatures.

Sophie Fletcher, 12, and her 10-year-old brother Jack are believed to have left their home in Darlaston, West Midlands, either overnight or early on Wednesday morning.

West Midlands Police said a large number of local officers were carrying out extensive inquiries to find the youngsters, who are thought to have packed a bag of clothes before leaving home.

The force said its search for the apparent runaways had been complicated by the closure of the local school, forcing officers to check dozens of addresses across a large geographic area.

It is believed that Jack and Sophie have taken money with them and may try to travel to Borth, near Aberystwyth, in Mid Wales. A police spokesman said: "There is now a suggestion that the youngsters may try to travel by train to a previous holiday destination in Borth, Wales."

Sophie is described as 5ft 2in with collar-length brown hair cut in a bob, and blue eyes. She is believed to be wearing a leopard-print coat with a hood which has small ears on it and purple trousers.

Jack is described as 5ft with straight blond hair and has a half-inch scar on his forehead. He is believed to be wearing a black hooded Benzini jacket with bright yellow lettering, black ankle boots and a cap with "NY" on the front.

Inspector Stuart Vaughan, of Walsall Police, said: "The children have not been missing before and, although they have packed clothes and taken money, we are very concerned about them, particularly in this cold weather. It is believed they have left of their own accord.

"We are continuing to carry out a number of inquiries to try and locate Sophie and Jack and are being supported by a significant number of force resources. We are now appealing to the public to help us with this search - if you have seen either of the children today or have any information about where they may be, please contact us immediately."

Anyone with any information should contact West Midlands Police on 101. A police officer who answered the door at the children's home in Darlaston said family members did not wish to speak to the media.