Clashes between Egyptian riot police and rock-hurling protesters in Cairo's Tahrir Square continue Sunday. Military police, backed by armored vehicles, launched a new assault, using clouds of tear gas, rubber bullets and batons to disperse the crowd.

At least 13 people are believed to have been killed in clashes in the past two days, while hundreds of soldiers and police are trying to evict several thousand protesters from the square, dismantling their tents and tearing down their banners. Around 1,000 people, including 40 policemen, have been injured.

Abdallah Abdelrahman, who heads a field hospital in Tahrir Square, told AFP that three of those casualties occurred Sunday due to asphyxiation, presumably caused by the tear-gas.

According to reports, most of Tahrir Square was covered with debris and shattered glass on Sunday following what is reported to be the worst standoff between police and protesters in months.

All roads leading to the square were blocked by protesters, who ran ID checks on anyone coming into the area.

Meanwhile, Al Jazeera quotes sources saying that the country’s Culture Minister Emad Abu-Ghazi resigns to object the use of excessive force against protesters.

­Watch the standoff between protesters and riot police on Sunday

Clashes in Cairo (AP still)

­The clashes have been ongoing since Friday, and on Sunday most of them took place on a road leading from the square to the Interior Ministry.

Internet social networks have called for Egyptians to join the demonstrations, with reports that several groups were headed to the square, including one from Cairo University.

Clashes in Cairo (AP still)

­According to Associated Press, hundreds of demonstrators threw stones at the main security headquarters in the city of Alexandria.

In the eastern city of Suez, about 1,000 people took to the streets outside a police station on Saturday night to show their support for the demonstrators in the country’s capital. Protesters in Suez tore down banners of former members of Mubarak’s party, who are running in the country’s first election since the ousting of President Hosni Mubarak in February.

Clashes in Cairo (AP still)

The recent violence brings fears of new unrest ahead of the parliamentary elections, set to start on November 28.

The military, which took over from Mubarak, has repeatedly pledged to hand over power to an elected government.  

But now reports suggest the handover, according to the military, will take place only after the presidential elections, which are slated to be held late next year or early in 2013.

Egyptian protesters point to the "Made in USA" tag on a tear gas canister during clashes with riot police at Cairo's landmark Tahrir Square on November 20, 2011. (AFP Photo / Khaled Desouki)

­But the protesters want a handover to take place immediately after the end of parliamentary elections in March.

One of the protesters at the scene explained Associated Press that public anger has risen over the slow pace of reforms.

“We joined the protest because none of goals of the revolution has been achieved and the slogans of the revolution, which are freedom, humanity and dignity, have not been fulfilled,” it quotes one of those rallying as saying.

Egyptian protesters lob stones as they face off against riot police during clashes at Cairo's landmark Tahrir Square on November 20, 2011. (AFP Photo / Khaled Desouki)