More than 50 Syrians were killed as tens of thousands of protesters rallied for a "day of rage" after Friday prayers, defying warnings of a harsh crackdown, rights activists and officials said.

Protests against President Bashar al-Assad's regime were held in most major towns, witnesses said, in pro-democracy demonstrations after the Muslim weekly prayers as on past Fridays.

Hamas chief Khaled Meshaal will meet next week in Cairo with Palestinian president and Fatah leader Mahmud Abbas to sign a unity deal, a senior Fatah official said on Friday, Agence France Presse reported.

It will be the first time the two men have met since Hamas took over the Gaza Strip in June 2007, forcibly ousting Fatah from the coastal territory after days of bloody street battles.

The al-Qaida terror network is among the suspects in connection with a bomb attack that killed 16 in the Moroccan city of Marrakesh, the government said Friday.

Communications Minister Khalid Naciri said that investigators would pursue all leads including possible links to al-Qaida which operates a North African offshoot which is active in the region, Agence France Presse reported.

Embattled President Ali Abdullah Saleh has accused Qatar of a "conspiracy" and threatened to pull out of a Gulf Cooperation Council (GCC) transition deal to end the violence in Yemen.

"Contacts are under way for the signing of the agreement on Monday in Riyadh, but we have reservations about some mediators involved in a conspiracy," Saleh said in an interview with the Russia Today television channel.

Human Rights Watch on Friday called for the United Nations Human Rights Council to investigate the deadly crackdown on protesters in Syria and to "strongly condemn repression of peaceful protests."

"Syria’s President Bashar Assad needs to hear an unequivocal message from the Human Rights Council that violent suppression of peaceful protests is unacceptable and will have consequences," said Julie de Rivero, Geneva director at Human Rights Watch.

Israel is "very concerned" about the implications of Egypt's plans to permanently reopen its border with Gaza, a senior official said Friday, warning it could impact on Israel's security, Agence France Presse reported.

Egyptian Foreign Minister Nabil al-Arabi told Al-Jazeera that the crossing would be permanently opened in coming days as part of Cairo's plans to ease the blockade on the Gaza Strip.

The World Bank said Thursday it would provide $10 million in aid to needy Palestinian families as a new unity deal between Fatah and Hamas raised questions about continued Western assistance, Agence France Presse reported.

The international body said the funds would go to 5,500 families in the occupied West Bank and the Hamas-ruled Gaza Strip, following a similar program in 2009 and 2010 that provided direct aid to some 25,000 families.

U.S. President Barack Obama must declare that his Syrian counterpart, Bashar al-Assad, has squandered his legitimacy and must step down, three key senators urged Thursday.

"We urge President Obama to state unequivocally -- as he did in the case of (Libyan leader Moammar) Gadhafi and (Egyptian President Hosni) Mubarak -- that it is time for Assad to go," Republican Senators John McCain and Lindsey Graham and independent Senator Joe Lieberman said in a joint statement.

Syria defiantly vowed to restore "security and stability" across the country despite growing international censure for its violent crushing of dissent, as activists called for more protests on Friday.

Growing anger at the regime's brutal crackdown on pro-democracy protesters, meanwhile, saw Britain on Thursday withdraw the Syrian ambassador's invitation to the wedding of Prince William and Kate Middleton.

A powerful blast ripped through a cafe in the Moroccan city of Marrakesh Thursday, killing 11 foreigners and three Moroccans in what authorities suspect was the work of a suicide bomber.

"According to the information I have, it could have been perpetrated by a suicide bomber," an official in the regional governor's office told Agence France Presse.