In a televised statement yesterday, Hazem el-Beblawi said the decision to break up the protests "was not easy" and came only after the government had given mediation efforts a chance.
"We found that matters had reached a point that no self respecting state could accept," he said, citing what he describes as "the spread of anarchy and attacks on hospitals and police stations".
Bulldozers were said to have been used to uproot the camps and drive out the protesters who were seeking Morsi's reinstatement after the 62-year-old Islamist was ousted by the military on July 3.
Conflicting reports emerged over the number of people killed yesterday as the death toll continued to rise.
The Egypt Independent reported that least 300 people were killed in Cairo yesterday after Egyptian security forces moved in to disperse thousands of supporters of Morsi who were protesting for weeks demanding his return in two major squares, Rabaa al-Adaweya and al-Nahda.
However, the Health Ministry said that at least 281 people were killed and over 1,400 injured in violent incidents nationwide yesterday. Forty-three members of Egypt's police force were among those killed, the ministry said.
The Muslim Brotherhood claimed that more than 2,000 people had been killed in the violence.
The government yesterday imposed a month-long emergency after riot police backed by armoured vehicles, bulldozers and helicopters swept away the two encampments of pro-Morsi supporters.
Security forces shot dead scores of people in their assault on the camps, defying international pleas to show restraint after a six-week stand-off with Morsi's Muslim Brotherhood supporters, Al Jazeera news channel reported.
Vice-President Mohamed ElBaradei resigned yesterday, saying peaceful means could still have been found to end the confrontation, but other members of the government have rallied behind the decision to use force.