By Asma Alsharif and Tom Perry
CAIRO (Reuters) - Egypt's military chief called for mass rallies on Friday to give him a mandate to confront violence following the overthrow of Islamist President Mohamed Mursi, appearing to raise the pressure on the Muslim Brotherhood.
General Abdel Fattah al-Sisi, who deposed Mursi on July 3 and replaced his government with an interim administration, also promised on Wednesday that there would be no retreat from the army-backed roadmap that envisions parliamentary elections in about six months.
"I request that all Egyptians next Friday ... go down (into the street) to give me a mandate and an order to confront possible violence and terrorism," he told a military graduation ceremony in remarks broadcast live by state media. Sisi also urged national reconciliation after months of upheaval.
A senior member of Mursi's Muslim Brotherhood movement, Essam El-Erian, said Sisi's appeal represented a threat, adding that it would not halt Islamist protests urging the immediate restoration of the president. "Your threat will not prevent millions from continuing to gather," Erian wrote on Facebook.
By contrast, the Tamarud youth group, which last month brought millions onto the streets of Egypt to denounce Mursi's first year in office, said on Facebook that it supported Sisi.
"We call all the great Egyptian people to gather in the squares of Egypt this Friday and to call officially for the prosecution of Mohamed Mursi and to support the Egyptian armed forces in its coming war on terrorism," the movement wrote.
A Western diplomat in Cairo, who declined to be named, said Sisi's appeal represented a risky gambit for the Arab world's biggest nation. "We have seen an increase in violence when the two sides come together," he said.
Sisi's speech followed an overnight bomb attack on a police station in Mansoura, 110 km (68 miles) north of Cairo, that killed one person and wounded two dozen others.
A government spokesman condemned it as a terrorist attack.
Mursi's Islamist backers accused security forces of conspiring to blame them for the bombing.
More than 100 people, most of them Mursi supporters, have been killed in street clashes this month. The Muslim Brotherhood says it has not and will not resort to violence.
With many of its top leaders in jail and Mursi in military detention, the Brotherhood says its supporters are being attacked by plain-clothes agents deployed by the authorities - a charge denied by security officials.
At least two more people died overnight on the streets of Cairo in protests against Mursi's overthrow. That followed nine fatalities in the capital on Tuesday, bloodshed underscoring the depth of the crisis facing Egypt and the interim government.
While Brotherhood supporters continue to voice outrage at the removal of Mursi, Egypt's first freely-elected head of state, some ordinary Egyptians say they are tired of the chaos.
Sisi, who was appointed head of the army by Mursi last August, has emerged as a national savior for those relieved to see the end of Brotherhood rule, his portrait appearing on Cairo street corners and in shop windows.
Starting his speech, Sisi, called for a minute's silence in honor of all the recent dead. Sounding relaxed and wearing dark glasses, Sisi said the army would never be divided, dismissing suggestions of a military schism following Mursi's downfall.
"This army only takes orders by the will and command of the Egyptian people," he said, denying he had betrayed Mursi and adding that the interim government would press ahead with plans to stage new elections swiftly.
"The coming elections will be decisive. If you have real weight and public opinion supports your movement, then that will be reflected in the coming vote," he said.
Yasser El-Shimy, an Egypt expert at the International Crisis Group, said escalating tensions risked the chances of establishing political stability in the future.
"Both the authorities and the Muslim Brotherhood should recognize the urgency of negotiating a compromise out of this ever-escalating impasse," he said.
(Additional reporting by Shadia Nasralla, Yasmine Saleh and Noah Browning; Writing by Tom Perry and Crispian Balmer; editing by David Stamp)