Egypt has begun work on a 20-meter deep moat to protect itself from Hamas in the Gaza Strip. The moat, which will be dug along the length of Egypt’s border, will be filled with seawater from the Mediterranean.

A zone of three to five kilometers has been cleared around the border, including home demolitions.

The aim is to prevent Hamas from digging tunnels under the border, through which it smuggles weapons, military personnel drugs and other contraband.

Hamas is an affiliate of the Muslim Brotherhood, the Islamist group which ruled Egypt after the 2011 revolution before it was deposed in a popularly-backed coup after just one year in office. Since then President Abdelfattah el-Sisi and the Muslim Brotherhood have been fighting a fierce struggle for control of Egypt.

The Muslim Brotherhood is suspected to have been behind the assassination of Egypt’s top prosecutor in June this year. Many of its leaders are in prison and have been sentenced to death.

The government of Egypt views Hamas as a threat due to its close association with the brotherhood. They further state that the Muslim Brotherhood caused the Islamic State to come into being.

Israel claims to have military intelligence that Hamas has been cooperating with the Islamic State’s Sinai Province, providing ISIS with weapons and treating ISIS fighters in Gazan hospitals. Egyptian military sources reported that Hamas members had fought the Egyptian army alongside ISIS but said they had not found evidence of wider institutional ties.

The moat is the next phase of a security plan that began in fall last year with the creation of a buffer zone on Egypt’s border with Gaza.