Police have appealed for a couple from Fraserburgh to make official contact to say they and their children are safe.
Officers want to trace Mark Hendry and Daniela Do Vale Goncalves, who are both 21, and their two children, Mark Hendry Jnr, aged 15 months, and two-month-old Chantelle Hendry.
Police said Ms Do Vale Goncalves and the girl had not been seen for two weeks.
Mr Hendry and the boy were last seen on Wednesday.
Officers have been checking airports and social media posts.
The social media posts have included Ms Do Vale Goncalves saying they are abroad on holiday.
Sgt Martin MacDougall, who is leading the investigation, said: "Enquiries were launched as the result of a well-intentioned and legitimate concern call made by a partner agency.
"As highlighted in our earlier appeals for information, whilst social media can be extremely useful in tracing missing people we have to be completely satisfied of the welfare of all those reported before we stand down our investigations, in particular when young children are involved.
"In the case of any missing person our ultimate aim is to ensure that those who have been reported missing have come to no harm when genuine concerns are raised.
"We are still in the process of officially confirming the exact location of the Hendry family with assistance from international counterparts and will provide an update as soon as we can."