Authorities in the Hamas-ruled Gaza Strip on Thursday closed local offices of Al-Arabiya TV and Palestinian news agency Maan for alleged "false" reporting of Hamas help for Egypt's Muslim Brotherhood.

"The Attorney General decided to close down Al-Arabiya and Maan offices in Gaza for distributing false news regarding the smear campaign against Hamas and Gaza about what's happening in Egypt," a Hamas official told Agence France Presse.

A Polish photojournalist has been kidnapped by masked gunmen in northern Syria, Reporters Without Borders (RSF) said on Thursday, calling for his "immediate and unconditional release".

Marcin Suder, a freelancer who works for the Corbis agency and other outlets, was abducted on Wednesday during a raid on a media center in Saraqeb, in the northwestern province of Idlib, RSF said.

Two U.N. envoys on a mission to persuade Syria's government to allow inspectors to probe alleged chemical weapons attacks ended a 24-hour visit Thursday, the United Nations said in Damascus.

Swedish scientist Ake Sellstrom and Angela Kane, the U.N. high representative for disarmament, "have left Damascus after an official two-day visit, during which the experts met with Syrian officials" including Foreign Minister Walid Muallem, said U.N. media and communications analyst Khaled Al Masri.

More than 100,000 people have now been killed in the Syria civil war, U.N. leader Ban Ki-moon said Thursday as he appealed for new efforts to convene a peace conference.

On the ground, violence raged in the flashpoint city of Homs and a car bombing in Damascus killed 10 people, the Syrian Observatory for Human Rights said.

French President Francois Hollande strongly condemned the killing of Tunisian opposition politician Mohammed Brahmi on Thursday and called on the country to unite behind its democratic transition.

"The president condemns in the strongest terms the assassination this morning in Tunis of lawmaker Mohammed Brahmi," Hollande said in a statement.

A car bomb attack on Thursday in the Jaramana suburb in southeast Damascus killed at least seven people and wounded 62, state television reported.

"The initial death toll for the terrorist car bomb blast in Jaramana is seven dead and 62 wounded," said the channel, adding that the condition of several of the wounded is "critical".

Egypt's military insisted Thursday that Islamists were not being targeted by its chief's call for an anti-terrorism rally, which the ousted Muslim Brotherhood has denounced as a declaration of civil war.

"General Abdel Fattah al-Sisi's call was not a threat to any political group in particular," the military spokesman said in a statement.

Syria's opposition National Coalition will meet in Istanbul on August 3 and 4 for talks on forming a provisional government, opposition sources said Thursday.

In Paris this week for meetings with French officials, Coalition vice president Suheir Atassi said opposition talks would be held on August 3 and 4 in order to "strengthen" the group's position.

A leading critic of Tunisia's ruling Islamists, MP Mohammed Brahmi, was shot dead outside his home Thursday in the second such assassination this year, with fingers again pointed at the authorities.

The murder by unknown gunmen sparked angry street protests in central Tunis and the top opposition figure's birthplace of Sidi Bouzid where he served as MP, Agence France Presse correspondents said.

Syria accused Washington on Thursday of applying double standards with its calls for a political solution to the country's conflict at the same time as talk of arming the rebels.

"Washington's decision to arm the terrorist groups in Syria proves that the United States (wants to) exacerbate the crisis in Syria, and shows up its dishonesty in the search for a political solution at a (proposed peace) conference in Geneva," a foreign ministry official said in a statement.