Video and Images of Anti-Morsi Protests As our colleagues David Kirkpatrick, Kareem Fahim and Ben Hubbard report from Cairo, millions of Egyptians packed the streets of cities across the country on Sunday to demand the resignation of President Mohamed Morsi, exactly one year after his inauguration as the country's first democratically elected leader. The Islamist president's supporters held a rival rally in Nasr City, a neighborhood in the capital. Video reports posted on YouTube by Ahram Online, an English-language offshoot of a state-owned Cairo newspaper, showed protesters outside the presidential palace in Cairo chanting "Leave!" as members of Mr. Morsi's Muslim Brotherhood rallied in support of what they called his legitimacy as an elected president. Participants in the rallies, as well as Egyptian journalists and foreign correspondents who witnessed the protests, uploaded images, video and text accounts of the massive crowds throughout the day and into the night. Once again, views of tens of thousands of protesters streaming into a packed Tahrir Square and swarming around the palace, known locally as the Itihadiya, were emblematic of the popular dissent. Bloggers who helped to document the initial phase of the revolution online reported on Sunday that sentiment against the Islamist president and the Muslim Brotherhood was now so strong it had swept up even formerly apolitical family members and the upscale part of the capital around the palace. The protests took place amidst an atmosphere of deep mistrust and tension between Mr. Morsi's supporters and opponents - last week even the nation's top Islamic cleric warned of "civil war" between the two sides. Early in the day, protesters shared images of anti-Morsi activists protecting the headquarters of the Muslim Brotherhood's political party. While the rival rallies remained peaceful throughout most of the day, tensions rose as night fell and local media began reporting clashes in cities outside of Cairo, including attacks on Brotherhood offices. In the days leading up to Sunday's protests both sides said they feared violence, but would also not shrink from defending themselves in the face of any attack, amid uncertainty about the loyalties of the nation's police force. A BBC correspondent, Jeremy Bowen, and Sherine Tadros of Al Jazeera, posted images on Twitter of Morsi supporters wearing martial arts gear and brandishing crude weapons. Sharif Abdel Koddous, a freelance journalist based in Cairo, captured a similar scene in video showing Brotherhood supporters in improvised armor, brandishing sticks. The Brotherhood's preparations were not just for show. Video posted online by Al-Shorouk, an independent Egyptian newspaper, appeared to show violent clashes at a the Muslim Brotherhood office in the rural province of Gharbiya, in the Nile Delta. In the clip, several men standing on the roof of the local Brotherhood headquarters could be seen firing guns at stone-throwing protesters. As shots rang out, men on the ground could be heard saying, over and over again, "What a dark day! What a dark day! Several correspondents, including our colleague David Kirkpatrick, remarked late Sunday that the police had seemed to withdraw from the streets and let events unfold. Sunday's protests were not the first sign of official anxiety about the police force and it's true loyalties. Egypt's police force spent decades rounding up and torturing the very Islamist groups who now run the country, and despite widespread anger over police brutality - one of the original sparks of the Egyptian revolution - Mr. Morsi has not undertaken security sector reform. This past winter, thousands of police staged a nation-wide strike, forcing the military onto the streets in cities along the Suez Canal. Another video clip from Al-Shorouk appeared to show members of different police force branches participating in anti-Morsi protests. It was not clear where the images were filmed, and at least one of the men shown in the video, who smiled and cheered for protesters while waving a small Egyptian flag, claimed that he was not against the government. "I'm not against the regime," he said. "I came because everyone is free," to express their opinions, he said. According to Priyanka Motaparthy, a researcher for Human Rights Watch, and Sherief Gaber, an activist blogger, police officers even took part in the demonstrations in Alexandria. As night fell on Sunday, an attack on the Muslim Brotherhood's national headquarters in Cairo hinted at the depths of Mr. Morsi's alienation when one of his official spokesmen accused Egypt's police force of participating in attempts to set it ablaze. Writing on Twitter, the spokesman, Gehad El-Haddad, accused the police force of participating in the attack in the office, located in the upscale Muqattam neighborhood, alongside "thugs." A television station linked to the Brotherhood, Misr 25, reported that "hundreds" of assailants were involved in the assault, although video shared by Mr. Haddad that claimed to show the attack depicted a far smaller number of people throwing rocks and Molotov cocktails at the building. A second video Mr. Haddad drew attention to, which appeared to be taken earlier in the day, shows young men outside the Brotherhood office breaking stones and hurling them at the building. Kristen Chick, Cairo correspondent for The Christian Science Monitor, reported from the scene of the attack on the Brotherhood headquarters that no police were visible early in the evening. Our colleague Kareem Fahim reported on Twitter later that the security forces did eventually appear at the Brotherhood headquarters, but departed half an hour later without intervening.