Egyptian soldiers on Gazan border (file)
Egyptian soldiers on Gazan border (file) Abed Rahim Khatib/Flash 90

Palestinians in Gaza and on social media are continuing to express outrage over the death of a naked man who was shot as he crossed from Gaza into Egypt, even as Hamas continues to hold a mentally unstable Israeli in Gaza.

Video has spread online purporting to show the man walking in the Mediterranean surf and crossing the posts and fencing marking the border between Gaza and Egypt, AFP reported Monday.

Egyptian guards open fire, while someone who appears to be part of the Gazan security forces appears to wave and signal to those shooting to stop because the man is mentally unstable.

The video, taken on Thursday, later shows the man's body on the shore. The Egyptian army has so far not commented on the incident.

Officials from Hamas, the Islamist movement that rules the Gaza Strip, say he suffered from mental illness, though the father of the Gazan man has been quoted as saying he did not.

The hashtag "Why did they kill him?" has since spread on social media and several dozen Gazans demonstrated on Sunday to demand Egypt return the man's body to his family, AFP reported.

Relations between Egypt and Gaza’s Hamas rulers have been tense since the 2013 ouster of Egyptian president Mohammed Morsi of the Muslim Brotherhood, Hamas’s parent movement.

Since that time, Egypt has cracked down on Hamas’s terror tunnels beneath the Egypt-Gaza Rafah border crossing, in an apparent attempt to prevent terrorist infiltrations.

Egypt accuses Hamas of providing Sinai-based terrorist groups with weapons for lethal attacks against Egyptian security forces. Hamas denies the charges.

As part of its fight against Islamist terrorism in the Sinai, Egypt established a buffer zone along the border with Gaza to prevent smuggling of weapons from Gaza terror groups into Egypt.

But as Hamas is outraged over the death of the Gazan, it continues to hold Avraham Mengistu, a mentally ill Israeli who crossed into Gaza in September 2014 and has been held by the group ever since.

Mengistu’s family on Saturday night condemned the terrorist group for its hypocrisy after Hamas issued harsh criticism against the Egyptian military.

"It is infuriating and shocking that the terrorist organization that is holding a mentally ill man, instead of returning him home as expected, dares to cry that 'this is an act worthy of condemnation and opposes the laws and humanitarian agreements,' and demands to put those responsible on trial," said Mengistu's family in a statement on Saturday night.

"This is the worst kind of hypocrisy."