Protesters, opposing Egyptian President Mohamed Morsi, take part in a protest demanding Morsi to resign at Tahrir Square in Cairo July 1, 2013. [Photo/Agencies]

CAIRO - At least eight people were killed during overnight clashes outside the Muslim Brotherhood (MB) headquarters in Cairo, raising death toll since Sunday's anti-president protests to 16, the country's health ministry official told Xinhua on Monday.

"The clashes killed eight at the MB headquarters, three in Assiut, one in Fayoum, one in Alexandria, one in Kafr al-Sheikh and one in Beni Suef, while at least 781 were injured," Health Ministry's spokesman Yahya Moussa explained, noting the one died near the presidential palace was out of suffocation.    

An eyewitness near the MB headquarters said that clashes between MB members and assailants from anti-president protesters erupted Sunday night.

"At least 43 others were injured near the headquarters," the eyewitness told Xinhua, adding that the six-story building contents were totally robbed and some floors were set on blaze.

The prosecution rushed to the scene for interrogations and the civil defense forces surrounded the area to disperse the crowds, added the witness.

Several MB headquarters in different governorates were attacked and torched during Sunday's mass protests, where hundreds of thousands of Egyptians flooded the major squares in the country on the first anniversary of Islamist-oriented President Mohamed Morsi to press him to step down and hold an early presidential election.

In the biggest protests Egypt has witnessed since the 2011 upheaval that toppled ex-president Hosni Mubarak, anti-Morsi protesters took to Tahrir Square and the vicinity of the presidential palace in Cairo, as well as several squares in other governorates, while the pro-president protesters continued their sit-in for the fourth consecutive day at Rabia al-Adawiya Square in Cairo's Nasr City "to defend legitimacy" of the first freely-elected president.