Cairo: The Egypt military warned that those threatening national security will be dealt with iron hand as the country sank deeper into bloody turmoil with at least 51 people being killed in clashes between army troops and Islamists protesting the overthrow of Mohammad Mursi.

The military urged Mursi’s supporters to end their sit-in protests, pledging that they would face no legal consequences for having joined in the demonstrations.

But spokesman Colonel Ahmad Ali warned against anyone approaching military facilities or threatening national security, in remarks at a news conference.

The Muslim Brotherhood from which Mursi hails accused the army of opening fire at “peaceful protesters” who had camped out the headquarters of the army Republican Guard in eastern Cairo since Friday, and urged Egyptians to launch an uprising to avenge what the group called a “massacre”.

“The demonstrators were the ones who started the attack, using live ammunition,” said Ahmad Ali. “All international laws give the right to guards of military installations in case of facing an armed assault to use all defence means,” he added.

Al Jazeera journalists have been kicked out of the news conference, most of them supporters of the ousted president.

During the news conference, one journalist stood up and demanded Al Jazeera reporters be excluded from the proceedings. The Al Jazeera reporters eventually stood up and walked out accompanied by chants of “Out! Out!” from others in the crowd.

Egyptian state television aired a video showing what the broadcaster said were Mursi’s supporters hurling hand grenades and petrol bombs at the army forces.

“The Brotherhood is committing suicide by provoking the army and causing further instability in the country,” said Amr Hashem, an expert at the state-run Al Aharm Centre for Strategic Studies. “The group is bent on playing the victim so as to earn the world’s sympathy and trigger international pressure on authorities in Egypt,” he added.

Hashem believes that the best way to “undermine the Brotherhood’s ploys” is to expedite the country’s transitional period.

“A new government should be formed immediately to set the scene for early presidential elections and leave the Brotherhood in no doubt that they will not return to power and that their tactics are doomed.”