Updated 3.30pm with PN statement
The home affairs minister has been urged to act against the director of studies at the Academy for Disciplined Forces, who suggested that Nationalist MPs should be pelted with eggs and tomatoes.
In the post, John Charles Ellul asked "are there any more eggs and tomatoes that can be hurled at the PN as they exit parliament?"
The post - which was not shared publicly - drew condemnation from the Nationalist Party as well as rule of law group Repubblika.
Both organisations described the post as "unacceptable" and unbecoming of someone responsible for training police officers, soldiers and members of other uniformed corps.
Repubblika president Robert Aquilina urged Home Affairs Minister Byron Camilleri to take action. He noted that Ellul is the brother of junior minister and government whip Andy Ellul.
Ellul is a former senior police inspector and forensics expert who also serves as a visiting lecturer within the department of criminology at the University of Malta. He had not yet made any public comment about the matter at the time of writing.