Egyptian President Mohamed Morsi has declared a 30-day state of emergency and a night-time curfew in three cities along the Suez Canal that have seen deadly clashes in recent days.

In a televised address late on Sunday, Morsi said the emergency measures in Port Said, Ismailia and Suez would take effect on Monday from 9:00pm local time (19:00 GMT) to 6:00am (04:00 GMT), warning that more action would be taken to stem the latest eruption of violence across much of the country.

"I have said I am against any emergency measures but I have said that if I must stop bloodshed and protect the people then I will act," Morsi said.

He also called for dialogue with top politicians starting on Monday to resolve the situation.

Deadly clashes across the country between protesters and police have killed at least 48 people since Friday, when Egyptians commemorated the two-year anniversary of the revolution that toppled former President Hosni Mubarak.

Seven people were shot dead and hundreds were injured in Port Said on Sunday during the funerals of at least 30 people killed during clashes in the city on the previous day.

"Down, down Morsi, down down the regime that killed and tortured us!" people in Port Said chanted as the coffins of those killed on Saturday were carried through the streets.

In Port Said, Al Jazeera's Rawya Rageh said military helicopters that had been overhead during the funeral could also be heard during Morsi's speech.

"I dont see how these decisions will instil any confidence in the people," Rageh said, referring to the president's decision to impose a state of emergency.

She said that immediate reaction in Port Said was one of mockery and scepticism with many asking why the three canal cities had been singled out.

"The people [in Port Said] feel that there was a complete state of collapse especially after riots today, particularly with tear gas being fired into the funerals," she said.

Protesters defiant

Several hundred people protested in Ismailia, Suez and Port Said after the announcement.

Activists in the three cities pledged to defy the curfew in protest at the decision.

On Sunday night, Morsi’s office issued a statement inviting political supporters and opponents for a national dialogue on Monday at 6:00pm (16:00 GMT) at the presidential palace in Cairo.

The spokesman for Egypt's main opposition coalition said after Morsi's speech that the move was "expected" and said he wanted more details about an invitation for dialogue with top politicians.

"Of course we feel the president is missing the real problem on the ground which is his own policies," Dawoud told the Reuters news agency.

"His call to implement emergency law was an expected move given what is going on, namely thuggery and criminal actions."

Hamdeen Sabahy, a leftist politician and opposition leader, said that he would not attend any negotiations "unless the bloodshed stops and the people's demands are met".

Mohamed ElBaradei, a leader of the NSF, said in a statement on Twitter that the dialogue was "a waste of time".

Heba Morayef of Human Rights Watch in Cairo said a state of emergency reintroduced laws that gave police sweeping powers of arrest "purely because [people] look suspicious".

"It is a classic knee-jerk reaction to think the emergency law will help bring security," she said. "It gives so much discretion to the Ministry of Interior that it ends up causing more abuse which in turn causes more anger."