From Wiki.

The (Egyptian)army said that "elements" in the Gaza Strip helped the perpetrators by firing mortars during the attack.[15] The daily al-Youm al-Saba'a quoted a senior Egyptian security official, who said that Islamic Jihad militants from Gaza and global jihad (Jihad al-Alami) fighters from Egypt perpetrated the attack.[16] CNN cited anonymous 'Egyptian general' who said the Hamas breakaway group 'Al-Galgala Army' is behind the border attack .[43] The MENA news agency said that the attackers were jihadists who had "infiltrated from Gaza through tunnels," and had collaborated with "jihadist elements."[15]
The Muslim Brotherhood released a statement calling on the government to "confront this serious challenge to the Egyptian sovereignty" as well as to "protect Sinai from all armed groups."[44] The party also claimed on its website that the attack "can be attributed to the Mossad", Israel's intelligence service, in an effort to destabilize the government, which the Israeli foreign ministry denied as "nonsense."[45]

On 7 August, at a funeral for the soldiers who were killed, Prime Minister Hesham Qandil was assaulted and attacked by angry mourners, who also vandalized his car. In addition, Kandil was pelted with shoes, while some angry mourners chanted, "The Brotherhood and Hamas are one dirty hand."[47]