* Opposition says call to topple government did not mean Mursi
* Two more protesters die of wounds, death toll 59
* President's office says to probe beatings
Egypt's main opposition alliance denied on Monday that it was demanding the overthrow of President Mohamed Mursi, backing away from an earlier statement that appeared to do just that.
Police and protesters clashed in the Nile Delta town of Al-Gharbiyah on Monday night as the National Salvation Front (NSF) struggled to clarify its position.
The protesters torched a police vehicle and attacked the governorate's office and police station, a security source. Police fired tear gas to disperse them.
After a week of nationwide violence between protesters and security forces in which 59 people were killed, the Front had issued a statement on Saturday calling for Mursi, his interior minister and other associates to be investigated and put on trial for "killings, torture and illegal detentions".
"The NSF will fully align with the demands of the Egyptian people calling to topple the regime of tyranny and domination of the Muslim Brotherhood," the statement said.
It said it supported peaceful protests to achieve these demands and called for Egyptians to rally in the streets.
However, NSF spokesman Khaled Daoud said on Monday the coalition of liberal, social democratic and leftist parties was not demanding the removal of the Islamist Mursi, who became Egypt's first democratically elected president seven months ago.
"We are not calling for the overthrow of President Mohamed Mursi right now. We believe he is elected but that doesn't give him the right to change all the rules of the game," Daoud said.
The Front includes liberal politicians such as former U.N. nuclear agency head Mohamed ElBaradei and former Arab League chief Amr Moussa, who last week signed a statement mediated by the country's leading Muslim scholar renouncing violence and calling for a national dialogue.
Ahmed Kamal, a spokesman for Moussa's Congress Party, said the wording had been chosen carefully to warn against "any violent practices and new dictatorship" without questioning Mursi's democratic legitimacy.
The Front said it would not engage in dialogue until what it called the bloodbath had stopped, those responsible were tried, and the opposition's previously stated demands were met.
Those demands include forming a national unity government, which Mursi has rejected before parliamentary elections due in April, and revising a controversial Islamist-leaning constitution adopted last December.
The statement was issued in reaction to an incident that provoked public outrage in which police were caught on video beating and dragging a naked man during a protest on Friday.
The man, Hamada Saber, 48, was shown on state television in a police hospital saying protesters had stripped him. He later reversed his statement and told a public prosecutor that riot police were responsible for the attack.
Another activist picked up by police in Cairo's central Tahrir Square on Jan. 25 and later taken unconscious to a hospital died of his wounds on Monday.
Mohamed el-Gendi, 23, was a member of the Popular Current party. Doctors at Hilal hospital said Gendi was in a coma when he died and had suffered brain damage and multiple fractures.
The president's office said it was investigating the causes of Gendi's death as well as the incident involving Saber, and insisted there would be no return to the violations of human rights that prevailed before the 2011 uprising that toppled former President Hosni Mubarak.
Opposition critics say little has changed, the interior ministry remains unreformed and the police have not been purged.
Earlier on Monday, a clash broke out when mourners carrying the body of a dead protester threw stones and metal objects at riot police guarding the British Embassy near Tahrir Square.
Police fired tear gas to disperse them.
The hardline Islamist Nour Party accused the opposition of stoking youth violence for political gain to try to oust Mursi.
The Salafist Nour Party condemned what it called unrealistic demands "such as overthrowing the legitimate president or calling for early presidential elections or calling for amendments to the constitution."