More than 1,000 illegal African immigrants in Israel staged a sit-in Saturday near the southern border with Egypt after a protest march against conditions in their internment camp.

"We are going to stay near the border with Egypt until a solution is found so our rights are respected," a statement by asylum-seekers at the Holot camp in southern Israel said.

Egypt's prosecution service on Saturday referred nearly 100 supporters of ousted president Mohammed Morsi to trial for alleged murders, a bombing and torching a university building, in two separate cases.

Morsi's Islamist supporters have faced a brutal police crackdown since his ouster by the army last July that has left more than 1,400 people dead and over 15,000 in jail.

Two bombings on Saturday in a Cairo suburb killed a teenager and her mother, officials said, the latest in a wave of blasts to hit the Egyptian capital this week.

Militants have stepped up attacks after the army ousted Islamist president Mohammed Morsi in July 2013 and amid a deadly crackdown by authorities on his supporters.

Nearly 1,000 illegal African immigrants in Israel on Friday staged a march towards the southern border with Egypt to protest against living conditions in their internment camp, public radio reported.

Israeli soldiers stopped the demonstrators, most from Eritrea and Sudan, nearly 300 meters (yards) from the border, it added.

Egyptian President Abdel Fattah al-Sisi landed in Islamist neighbor Sudan on Friday for what an analyst said would be an attempt to shore up a regional alliance against Islamic "terrorism".

An AFP photographer at Khartoum airport confirmed the Egyptian leader's plane had touched down.

Egyptian President Abdel Fattah al-Sisi warned Thursday that Africa was facing a "plague" of cross-border terrorist groups at the opening of an African Union summit in Malabo.

"Africa is threatened by cross-border terrorism," Sisi said, calling on leaders gathered in the capital of Equatorial Guinea to "firmly face up to this plague to preserve the dignity of our people and economies."

An Al-Jazeera journalist whose jailing triggered global outrage has donated 15,000 Egyptian pounds to a fund initiated by the president to boost Egypt's ailing economy, his brother said on Thursday.

Egyptian-Canadian Mohamed Fadel Fahmy, who was sentenced to seven years in jail along with two other Al-Jazeera journalists for allegedly aiding the blacklisted Muslim Brotherhood, made the donation to Tahya Misr (Long Live Egypt), an initiative of President Abdel Fattah al-Sisi.

An Egyptian court has sentenced a Coptic Christian man to six years in jail for insulting Islam and stirring up sectarian strife in his village, his lawyer told AFP on Wednesday.

Egypt's constitution outlaws insults against the three monotheist religions recognized by the state -- Christianity, Islam and Judaism.

Four makeshift bombs exploded within minutes of each other at three Cairo metro stations during morning rush hour on Wednesday, wounding at least two people, Egyptian police said.

One bomb went off at the station of Ghamra, in central Cairo, while the others occurred at Shubra el-Kheima and Hadayek al-Kobba on the outskirts of the capital, a police official told Agence France Presse.

A trip to Egypt is currently not on the agenda of Prime Minister Tammam Salam, officials said in remarks published on Wednesday.

The officials, who are close to Salam, told al-Liwaa newspaper that Salam is not planning to visit Cairo anytime soon although he is ready to accept official invitations that he receives from Arab and friendly countries.