The post called for the "whole community" of Diaz's native Barranca, Colombia to come together and march for his father Luis Manuel and "free him now".
InstagramThe event took place on Tuesday afternoon, local time, with supporters lining the streets with white balloons and chanting for Luis Manuel's release.
Diaz's reposting of the advertisement marks his first public statement since news broke of his parents' kidnapping on Sunday.
It is thought that both Luis Manuel and Diaz's mother, Cilenis Marulanda, were out buying watermelons when they were taken by four armed men on motorcycles. Marulanda was later released, but Luis Manuel's whereabouts remain unknown.
The latest information from Colombia has sparked new fears that Diaz's father may no longer be in the country.
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The Daily Mail reports that police are considering the possibility that Luis Manuel may have been smuggled over the border into Venezuela, as patrol searches continue across the nearby Perija mountain range.
However, Colombia's national police director General William Salamanca - who joined the search on Monday - has quelled notions that Diaz's father may be located in Venezuela due to the difficulty of crossing said range.
Given the ongoing situation, Diaz was absent from Liverpool's 3-0 victory over Nottingham Forest on Sunday. The Colombian was honoured by Diogo Jota during the match with a touching celebration tribute, who also spoke on the player's "unimaginable" situation.