The latest sighting at 10:36 at Piccadilly bus station on Monday follows a previous one earlier that morning when Lillia was seen boarding the number 36 bus from Salford.
Ch Supt Helen Critchley said: “Officers are making every effort to locate Lillia, and our team have been working through hours of CCTV footage and exploring every avenue to try and find her.
“I can now confirm that our last known current sighting was of Lillia at Manchester Piccadilly bus station at 10.36am on the morning of Monday 14 September.
“We can also share that she exited the number 36 bus at Piccadilly, with her boarding it in Salford.
“That bus service travels from Bolton through Salford and into Manchester city centre.
“If anyone has any information regarding Lillia’s whereabouts or movements from this bus – or you were on the bus at the time she was also on there or when she got on in Salford or off in Piccadilly – please contact us via 101 or the Major Incident Portal below.”