Mengistu has now been held for a total of 1,000 days since he voluntarily crossed the border. His family have said that he suffers from mental health issues.
Demonstrators held signs declaring support and love for the young man and his family, while also proclaiming that he is still alive and saying that the government should be doing more to secure his release.
Mengistu's family also attended the protest, where his mother Agranesh said, "I'm broken from the thought that after so many days I don't know if my son has seen a doctor, received medical treatment or even what his medical condition is. I'm full of hope that people will see that my son is sick and what happened to me can happen to everyone."
Ilan Mengistu, Abera's brother, criticized the government for not doing more, saying, "The government denies and ignores its moral obligation to return an Israeli citizen to his home."
Mengistu, originally from Ashkelon and suffering from mental illness, crossed the border with the Gaza Strip three years ago and has since been held by Hamas.