Three homemade bombs have exploded near Egypt's presidential palace, killing two senior police officers and injuring 10 other people on the anniversary of mass protests that led to the ouster of Islamist President Mohammed Morsi.
The devices were planted on Monday (local time), less than 20 metres away from the walls of the Ittihadiya palace in the upscale Heliopolis district in eastern Cairo, in what appeared to be a serious security breach in the heavily policed area.
It was not immediately clear whether President Abdel-Fattah el-Sissi, who as army chief ousted Morsi last summer, was inside the palace when the explosions occurred.
In a nationally televised speech from the palace later, el-Sissi said the government will spare no effort to go after the culprits and will issue legislation to deter those seeking to destabilise the country.
He did not elaborate, but the government has drafted an anti-terrorism bill that has been delayed by criticism from human rights organisations and liberal politicians as well as the absence of an elected parliament.
"Black terrorism is still trying to stand between the Egyptians' will, their hopes and aspirations, a terrorism that knows no religion or nation," el-Sissi said in a pre-recorded speech. "I promise God, their families and their pure souls that the state will avenge their deaths justly and fast."
El-Sissi stressed that the fight is a regional one, in which he will be cooperating with Arab countries, pushing "new blood" into joint action.
"We will continue to defend our religion and we will deal firmly and forcefully with reactionary forces," he said.
The government holds Morsi's Muslim Brotherhood group responsible for the violence that followed his ouster, claiming is seeking to destabilise the new order in cooperation with radical Islamists.
In a stunning reversal of fortunes, the government declared the 86-year old group, which rose to power after Egypt's 2011 uprising, a terrorist organisation. It has arrested thousands of its members and froze the assets of its senior leaders.
Hundreds of its members, including Morsi, face trials on multiple charges such as inciting violence and conspiring with foreign groups to undermine Egypt's security.
The Brotherhood denies the charges, and says the accusations are part of a political crackdown seeking to defame the group.
Saudi Arabia and other rich Gulf countries also oppose the Brotherhood and have supported el-Sissi's overthrow of Morsi. They offered Egypt substantial financial aid to meet a gruelling economic crunch following years of turmoil.
There was no immediate claim of responsibility for the Monday blasts, which took place on the second day of the holy month of Ramadan, but they bore the hallmarks of Islamic militant groups sympathetic to Morsi. A militant group that has claimed responsibility for previous attacks on police said in a statement dated June 27 that it had planned to plant bombs around Ittihadiya but aborted the attack earlier this month.
Ajnad Misr, or Soldiers of Egypt, said it planted explosives near the palace on June 18 to hit its security contingent. But it said it aborted the attack because civilians came close to the explosives. It said its operatives were unable to retrieve the devices but have been diverting civilians away from them. The statement's claims could not be verified and it was not clear if the assertions were connected to Monday's blasts.
Security officials said the first bomb to go off on Monday slightly wounded three street cleaners, while a second and third exploded while bomb squad teams were trying to defuse them, killing a police colonel and a lieutenant-colonel, and wounding seven other people. Another device in the area was discovered and safely defused, according to the officials, who spoke on condition of anonymity because they were not authorised to speak to reporters.
An Associated Press video showed the immediate aftermath of the second explosion, with plainclothes police carrying away the dead colonel and an injured policeman as a cloud of white smoke rose from the site.
Security forces sealed off roads leading to the palace.
On the other side of town, security forces sealed off Tahrir Square - epicentre of the 2011 uprising that toppled longtime ruler Hosni Mubarak - to search for explosives.
Celebrations were expected there later Monday to commemorate the start of several days of protests last year in which millions demanded Morsi step down. The protests culminated in Morsi's removal by the military on July 3.
El-Sissi has since retired from the army and was elected president in May for a four-year term.
By late Monday, the square remained closed to traffic and no party took place amid tight security around all of its entrances.
Meanwhile, in a move that raises the possibility of renewed street violence, a Brotherhood-led alliance called for nationwide protests on Thursday to mark the anniversary of Morsi's overthrow.
Past attempts by Morsi supporters to stage mass street protests have been harshly dealt with by security forces, part of the government crackdown that has over the past year killed hundreds.
"July 3 will be a day of rage that will be the beginning of the end, or a day of rage that paves the way for a decisive stage," the so-called National Alliance for the Defense of Legitimacy said in a Monday statement. It called on its supporters to march to Tahrir square from 35 mosques in Cairo and pleaded with police and army troops not to confront the protesters.