Police are appealing for information following an incident in which a man asked two girls to get into his van.
The incident occurred at around 3.10pm on Tuesday as the two girls – aged 15 and 16 – were standing at the junction of Church Street, St James Street and Hall Street in Burnley town centre.
It is believed a man in a white Renault panel van pulled up alongside them and asked the girls to get in, before claiming to be a taxi driver.
The girls refused and the man drove off.
He is described as Asian, aged in his 40s, with a beard or stubble and was wearing a blue, short-sleeved top.
Det Ch Insp Tim Brown said: “We are taking these reports extremely seriously and are now asking anybody with information about what happened to get in touch with us.
“Maybe you saw all or part of the incident, have dashcam footage showing the van in the area at the time, or maybe you think you know who is responsible. Whatever information you have, please contact us straight away.
“We appreciate this incident will have caused worry in the local community and we want to reassure you we are working extremely hard to get to establish what happened.
“In the meantime we have stepped up patrols in the area and anybody with concerns is welcome to speak to an officer. We would also urge people to remain vigilant and report any suspicious behaviour to us straight away.
“Finally, we know how rumours can spread on social media, so we would also ask people to only get their information from police channels, and to refrain from speculating further on what might have happened until the full circumstances have been established.”
Anybody with information is asked to get in touch on 101, quoting log 964 of July 20.
Alternatively independent charity Crimestoppers can be reached on 0800 555 111 or at crimestoppers-uk.org.