Cairo - An al-Qaeda inspired group in Egypt posted a video online Thursday showing a suicide bomber attacking a security headquarters in the Nile Delta city of Mansoura, an assault that killed 16 people in December.
The video by Ansar Beit al-Maqdis, or the Champions of Jerusalem, also said the suicide bomber previously was injured in Islamist demonstrations against the ouster of Islamist President Mohammed Morsi by Egypt's military.
The comment marks the first time a suicide bomber in the widening campaign of militant attacks striking Egypt has been directly linked to demonstrating Morsi supporters.
The 16-minute video named the bomber as Imam Mahfouz or Abu Mariam. It showed footage of him, wearing a white robe sitting next to Kalashnikov assault rifles, criticizing the Egyptian military for protecting Israeli and helping Syrian President Bashar Assad in his civil war.
"Those of the military are who are killing Muslims ... must be killed," he says. "We kill as they killed."
The video then shows the attack at Mansoura from a distance. Militants posted the video on a website often used by the group and it corresponded to earlier reporting done by The Associated Press.
Ansar Beit al-Maqdis first arose in the Sinai Peninsula, where for years militant groups largely made of up local Bedouin had carried out attacks, lobbing rockets into neighbouring Israel and opening fire on soldiers and police officers. Attacks escalated after the 2011 fall of autocrat Hosni Mubarak, but increased dramatically after Morsi's overthrow.
Egypt's military-backed interim government has blamed Morsi's Muslim Brotherhood group for the violence, outlawing it and calling it a terrorist organisation after the Mansoura bombing. The Brotherhood denies being involved in the violence, though the video released on Thursday is the first time a suicide bomber has been identified as a Morsi supporter.
On Wednesday, the United States designated Ansar Beit al-Maqdis a foreign terrorist organisation.