|Protesters have demanded that police officers who killed anti-Mubarak demonstrators be tried Reuters]
A group of armed men has attempted to disrupt a sit-in taking place in Cairo's Tahrir Square, injuring at least eight people, security sources have told Al Jazeera.
The men approached the square, which is being occupied by protesters demonstrating against the government, armed with knives on Tuesday, and attempted to force their way into the central space.
They fought with protesters when they attempted to bypass the civilian-manned checkpoints set up on the periphery of the square. Two of the men were apprehended by protesters, who called the military to detain the suspects.
Waleed Soud, a protester, told the Associated Press news agency, that the attackers also threw rocks at the anti-government demonstrators.
More than a thousand demonstrators continued their protest after the altercation.
Tuesday's attack came ahead of a planned mass rally that was slated to take place later in the day. Such attacks were common during the 18-day uprising that led to the exit of Hosni Mubarak, the former president.
The country's Supreme Council of the Armed Forces (SCAF) released a short statement on Tuesday warning protesters against "harming public interests".
The statement repeated steps announced several times over the last few month that the military ruling council would hand political power to a civilian administration.
General Mohsen El-Fangari, SCAF spokesperson, said the council is commited to holding parliamentary elections, followed by the drafting of a new constitution and then presidential elections.
Demonstrators, however, say they remain frustrated with the pace of change in Egypt, after the head of the security forces defied orders from the prime minister to dismiss police officers who had been accused of killing protesters during the uprising against Mubarak.
Protesters have been camping out in Tahrir Square, as well as in Suez and other cities, since Friday, demanding the resignation of the interior minister, a more active purging of the bureaucracy of former Mubarak loyalists and a plan to overcome economic issues.
"The military council is following the same policies as the ousted regime," said Mohamed Abdel Waged, 43, a teacher who has camped for several nights in Tahrir Square.
Dozens of demonstrators in the port town of Alexandria also held protests on Tuesday, chanting slogans against Field Marshal Mohamed Hussein Tantawi, the head of the SCAF.
Al Jazeera's Ayman Mohyeldin said, "Over the past 72 hourse we have now seen two statements from the Prime Minister Essam Sharaf and the statement that was released today by the Supreme Council of the Armed Forces.
"Neither of those statements seems to have done anything to alleviate the anger that exists amon the protestors."
Prime minister isolated
Essam Sharaf, the prime minister, has found himself isolated in between protesters who say that change must come faster, and running the caretaker civilian government.
Over the weekend, Sharaf told Mansour al-Issawi, the interior minister, to fire 400 police officers who had been accused of killing protesters. Nearly 900 people were killed during the uprising.
Al-Issawi responded by saying that summarily dismissing the officers would be illegal.
The dispute has now put Sharaf's credibility with the public on the line.
Sharaf had earlier said on his official Facebook page that he was due to make an important announcement on Monday, prompting speculation that he may have been planning on shuffling his cabinet.
He later backtracked, saying that changes would be announced but that it would only be done later in the week.
Police officer trials
Tensions remain high on the streets, and the release on bail last week of seven police officers on trial for killing protesters in Suez sparked days of rioting in that city, 100km east of Cairo.
"We have all the evidence that proves police officers killed the protesters," said Ali el-Genadi, father of one of the protesters who was killed in Suez. "We are not against the law, but we are against the judges who implement the law."
Protesters came out in their tens of thousands to demand that al-Issawi be dismissed as interior minister and that police officers be brought before the courts to answer charges of killing protesters.
A hard core of activists began the Tahrir Square sit-in that night. They have vowed to stay until their demands are met.
Ahmed Ragab, a spokesman for an association of police officers, said that Sharaf's order for the officers' dismissal is illegal and unjustly implies that officers who were defending police stations acted in the same manner as snipers who shot anti-government protesters.
"We, too, demand retribution for the martyrs of the revolution," said Ragab, who says his association has the support of some 15,000 senior police officers.