CAIRO, Aug 18 (Aswat Masriya) - Muslim Brotherhood supporters staged 138 protests on Thursday, Friday and Saturday in commemoration of the first anniversary of the deadly dispersal of two pro-Mohamed Mursi camps last August, said Democracy Index.

The dispersals, which took place on August 14 2013, left hundreds killed and were described by international watchdog Human Rights Watch as "the most serious incident of mass unlawful killings in modern Egyptian history."

In a report released on Monday, the Cairo-based Democracy Index said the majority of protests, 70, were held on Thursday, August 14. Friday witnessed 53 protests while Saturday witnessed 15 protests.

Saturday also marked the first anniversary of deadly clashes between security forces and Muslim Brotherhood sympathisers which left at least 173 killed. 

Protests were held in 20 governorates, the report said. Alexandria saw the majority of protests, 15, while Giza ranked third with 13 protests and Cairo ranked fifth with 10 protests.

The index said the level of violence during the dispersals' anniversary exceeded previous events, with 49 acts of violence reported.

The violence included 23 incidents of clashes between security forces, Muslim Brotherhood protesters and other residents, eight incidents of torching governmental buildings, police vehicles and public transport buses, five incidents of targeting electric pylons and five explosions. They also included two incidents of torching privately-owned vehicles, two armed attacks on police forces and detonating one mobile phone tower.

Democracy Index also reported three attacks on journalists covering the protests.

The New York-based Committee to Protect Journalists (CPJ) said in a Friday report that six journalists were attacked by security forces, pro-government supporters and Brotherhood supporters on Thursday. Five journalists were also "briefly detained" by security forces while covering the protests, CPJ added.

"It is disheartening to see journalists continue to be assaulted on the anniversary of the deadliest day for journalists in Egypt," said Sherif Mansour, CPJ's Middle East and North Africa program coordinator.

At least three journalists were killed while covering the forcible dispersal of the pro-Mursi Rabaa al-Adawiya sit-in in Cairo last August.

The protests commemorating the dispersal soon devolved into clashes leaving at least nine killed, including one policeman, according to Khaled al-Khatib, the head of the health ministry's critical care unit.

Interior Minister Mohamed Ibrahim said on Sunday that the ministry "succeeded in thwarting the terrorist Muslim Brotherhood's plot to disrupt the state's public utilities," reported MENA. He added that security forces were also able to dismantle Improvised Explosive Devices (IEDs) planted to "terrorise citizens." Democracy Index said security forces dismantled 30 explosive devices.

The ministry said it arrested 193 protesters on Thursday, while the Index reported over 200 arrests throughout the three days of protests.

Democracy Index is a research project issued by the Cairo-based International Development Centre.