The Egyptian government on Wednesday formally declared the Muslim Brotherhood as a terrorist organization and banned its protests nationwide Al Arabiya reported.
Minister of Higher Education Hossam Eissa read out the Cabinet statement after a long meeting on Wednesday.
"The Cabinet has declared the Muslim Brotherhood group and its organization as a terrorist organization," Eissa said.
Interim Prime Minister Hazem el-Beblawi previously described the Muslim Brotherhood on Tuesday as a terrorist group following a deadly attack on a security building in the city of Mansoura.
Saudi Arabia, which backed the Egyptian government after Mursi's ouster, condemned terrorism in Egypt on Wednesday. A Royal Court statement said the kingdom "stand heart and mind with its Egyptian brothers."
The attack killed 14 people and wounded at least 130 others and came just weeks before a referendum on a new constitution that is billed as the first major step toward democracy since the military-backed ouster of Islamist president Mohammad Mursi in July.
The government blamed the Islamist group for the bombing saying: "all of Egypt was horrified by the ugly crime committed by the Muslim Brotherhood on Tuesday morning, when it blew up the Daqhaleya police headquarters."
The Muslim Brotherhood and the so-called anti-coup alliance, however, condemned the attack saying they activities do not include violence and accused the notorious security regime of former President Hosni Mubarak, which they say has returned, of plotting the bombing and blaming it on the Muslim Brotherhood.
"The Muslim Brotherhood considers this act as a direct attack on the unity of the Egyptian people and demands an enquiry forthwith so that the perpetrators of this crime may be brought to justice."
The state-run Middle East News Agency quoted Beblawi as saying that those responsible for blast "will not escape punishment."
The impact of the explosion was felt around 20 kilometers away and shattered windows of nearby buildings, the security sources said.
The head of security for Daqahleya, Sami El-Mihi, was wounded in the blast and two of his aides were killed, security sources said.
There has been widespread bloodshed in Egypt since Mursi's ouster.
He was forced from power on July 3 after massive street protests against his turbulent one-year rule, with millions accusing him of power-grabbing and economic mismanagement.
More than 1,000 people have been killed in a government crackdown on his supporters, mostly from the Brotherhood.
The crackdown has also seen thousands of Islamists, including the entire leadership of the Brotherhood, arrested.
The movement's top leaders -- including its general guide, Mohammad Badie -- have been put on trial. Mursi too is on trial over several charges including some related to the deaths of protesters during his presidency.