Turkey's prime minister lashed out Saturday at the international response to the escalating crisis in Egypt, saying organizations including the U.N. and EU should be ashamed of their "inaction."

"Let me say very clearly, the United Nations Security Council no longer has the right to look at itself in the mirror, it's so ashamed, because it couldn't condemn what's happening in Egypt," said Prime Minister Recep Tayyip Erdogan.

Thousands of Arab supporters of the Islamic Movement in Israel demonstrated on Saturday in support of Egypt's ousted Islamist president Mohammed Morsi, an Agence France Presse correspondent said.

Around 4,000 people led by firebrand preacher Sheikh Raed Salah, head of the northern branch of the Islamic Movement, took part in the protest in the northern city of Nazareth, the correspondent said.

Thousands of supporters of Egypt's ousted leader Mohammed Morsi took to the streets in Turkey on Saturday to denounce "massacres" of his loyalists.

Some 4,000 people gathered at a mosque in Istanbul shouting "Down with (army chief Abdel Fattah) al-Sisi" and "Morsi in power!" an Agence France Presse photographer reported.

A bomb exploded Saturday in front of Egypt's consulate in the eastern Libyan city of Benghazi, causing no casualties but some damage, a security official said.

"Unknown assailants in a vehicle threw an explosive device at the Egyptian consulate in Benghazi without causing casualties," said security spokesman Abdallah al-Zayedi.

Egyptian authorities have arrested Mohamed al-Zawahiri, brother of al-Qaida head Ayman al-Zawahiri, for supporting ousted Islamist president Mohammed Morsi, a security source told Agence France Presse on Saturday.

The brother was arrested in his home district of Giza, adjacent to the capital, the source said.

The son of Mohammed Badie, supreme guide of Egypt's Muslim Brotherhood, was killed in violence between protesters and security forces on Friday, the group's political arm said on Saturday.

"Ammar, son of Dr. Mohammed Badie, the Supreme Guide of (the) Muslim Brotherhood, (was) killed by live ammunition in yesterday's massacre in Ramsis Square," the Freedom and Justice Party said in a statement.

Egypt briefly reopened the Rafah crossing on Saturday for humanitarian reasons to allow in some 50 people who were stranded in the Gaza Strip, the Hamas interior ministry said.

Egypt had on Thursday announced it was closing "indefinitely" the only crossing -- the only route into the Hamas-ruled coastal enclave that bypasses Israel -- for security reasons a day after deadly violence nationwide.

The trial of former Egyptian President Hosni Mubarak on charges of complicity in the deaths of protesters was adjourned on Saturday until August 25, after a brief session.

Mubarak, 85, and his former interior minister, Habib al-Adly, are on trial with six members of the regime overthrown in a 2011 uprising.

Venezuelan President Nicolas Maduro recalled his ambassador to Cairo on Friday and called for Egypt's ousted president Mohammed Morsi to be reinstated.

He also urged the restoration of constitutional order in Egypt, where more than 600 people have been killed in protests since Wednesday.

Egyptian police cleared Islamist protesters from a Cairo mosque on Saturday after a standoff that included exchanges of fire, as the death toll from four days of violence surpassed 750.

Security forces dragged supporters of deposed president Mohammed Morsi from the Al-Fath mosque, passing through angry crowds who tried to beat the Islamists, calling them "terrorists".