North Yorkshire Police yesterday launched an appeal as they searched for Thi Phan, 15, and 14-year-old Tram Le.
They were last seen near York Minster at around 12.30pm yesterday.
Chief Inspector Al Wescott, one of the officers leading the search, said: Our officers are working around the clock to try to find Thi Phan and Tram Le and today we’ve been exploring a number of lines of enquiry.
The public’s help could be vital, and we’d urge anyone who thinks they may have seen the girls to get in touch immediately. Any information, no matter how insignificant it may seem, could help our investigation.
The girls, who now live in the York area, are both around 5ft 2ins tall.
Tram Le was wearing a blue and white top and black trousers. Thi Phan was wearing jeans and a baggy shirt.
Police are urging anyone with information to contact 101 immediately, select option 1 and quote reference number NYP09072017-0296.