A roadside bomb claimed by the Islamic State group killed three Egyptian soldiers in the Sinai Peninsula on Monday, medical and security officials said.

The blast struck on the Egyptian side of the divided city of Rafah on the Gaza border, the official said.

The United States on Sunday condemned the "brutal mass murder" of 30 Ethiopian Christians in Libya following a video released by Islamic State militants purportedly showing their execution.

The 29-minute IS video appears to show militants holding two groups of captives, described in text captions as "followers of the cross from the enemy Ethiopian Church".

An Egyptian court Sunday sentenced to jail a man convicted of spying for Israel in the Sinai Peninsula where security forces are fighting an Islamist insurgency, judicial officials said.

Two Israeli accomplices of the jailed Egyptian were tried in absentia and also given life terms, the officials added.

More than 30 percent of young Arabs are jobless because of unrest in many Arab nations and not enough investment, a top labor official said on Sunday.

"The unemployment rate among Arab youth until the age of 30 years exceeds 30 percent," the director general of the Arab Labor Organization Ahmad Mohammed Luqman told AFP.

Arab military chiefs will meet this week in Cairo to discuss the forming of a joint military force to fight the region's growing extremist threat, an Arab League official said Sunday.

After Arab League leaders agreed to create such a force at a March summit in Egypt, army chiefs from member states will hold talks on Wednesday on details of how the force will be created, its role and its financing, a League source told AFP.

Archbishop of Canterbury Justin Welby, the Church of England leader, offered his condolences to Egyptian officials Sunday over the beheadings of 21 Coptic Christians by jihadists in Libya.

The Copts, 20 of them Egyptian, had traveled to Libya for work. They were kidnapped and executed by Islamic State militants in February, provoking Egyptian air strikes on IS targets in the strife-torn country.

Egypt's ex-president Mohamed Morsi faces being sentenced to death Tuesday on charges of inciting the killing of protesters in the first verdict against him nearly two years after his fall from power.

He also faces the death penalty in two other trials, including one in which he is accused of spying for foreign powers, and escaping from prison during the 2011 anti-Mubarak revolt.

Al-Mustaqbal movement leader ex-PM Saad Hariri is expected to travel to Washington on Monday for a one week visit, al-Joumhouria daily reported.

The agenda of his trip is still not complete, the newspaper said Friday.

Egypt's government on Wednesday approved the demolition of the headquarters of the once-dominant party of toppled president Hosni Mubarak that was torched during the 2011 uprising.

Angry protesters demanding the ouster of Mubarak's regime ransacked and set fire to the headquarters of his National Democratic Party (NDP), located in the heart of Cairo near Tahrir Square, epicenter of the uprising.

Two Egyptian military cadets were killed in a bombing north of Cairo on Wednesday as they waited to board a bus, officials said.

The blast struck in the Nile Valley city of Kafr al-Sheikh and wounded 10 other people, police officials said.