Hamas has been accused of providing weapons , training and fighters for Sinai-based insurgent attacks , although Hamas strongly denies the allegations , calling them a smear campaign aiming to harm relations with Egypt . According to the Egyptian Army , since the ouster of Egypt 's Muslim-Brotherhood president Mohamed Morsi , over 600 Hamas members have entered the Sinai Peninsula through smuggling tunnels . In addition , several weapons used in Sinai 's insurgent attacks are being traced back to Hamas in the Gaza Strip , according to the army . The four leading insurgent groups in the Sinai have all reportedly maintained close ties with the Gaza Strip . Hamas is also accused of helping Morsi and other high-ranking Egyptian Muslim Brotherhood members break out of the Wadi Natroun prison in Cairo during the 2011 revolution . Hamas called the accusation a " dangerous development " . Egyptian authorities stated that the 2011 Alexandria bombing was carried out by the Gaza-based Army of Islam , which has received sanctuary from Hamas and earlier collaborated in the capture of Gilad Shalit . Army of Islam members linked to the August 2012 Sinai attack have reportedly sought refuge in the Gaza Strip . Egypt stated that Hamas directly provided logistical support to the Muslim Brotherhood militants who carried out the December 2013 Mansoura bombing
2011 Alexandria bombing
2011 Alexandria bombing
Hamas