Two bomb blasts were reported in Cairo on Saturday as Egyptians marked the third anniversary of their Jan. 25, 2011 uprising.
One bomb exploded near a police academy in Cairo, wounding one person, security sources said.
The blast was sparked by what was described as a small "incendiary bomb" lodged on the wall of the police training center and exploded without causing any casualties, a police official told Agence France-Presse. It was thrown by an assailant, who later escaped, the official added.
The second blast was reported in Hadaeq al-Quba, a Cairo district. Details of this attack remain unclear.
Following a string of deadly bomb attacks a day earlier, Egypt on Saturday woke up to the third anniversary of the uprising on a tense note.
A series of bomb attacks in Cairo and clashes across the country on Friday left at least six people dead and wounded several others.
Rival political groups in the country are set to mark the 2011 uprising which ended in the overthrow of President Hosni Mubarak with planned protests across the country.
The Muslim Brotherhood has held regular protests since the military, led by Gen. Abdel Fattah al-Sisi, ousted Islamist President Mohammad Mursi last July.
The Anti-Coup Alliance, led by Mursi's Muslim Brotherhood, called in a statement for 18 days of protests beginning on Saturday, mirroring the 18 days of protests that led to Mubarak stepping down in 2011.
The 2011 revolt raised hopes of a stable democracy in the Arab world's biggest nation. Instead, relentless political turmoil has hit investment and tourism hard in Egypt.
The government has said extra security measures are in place for Saturday.
"We have a plan to secure all of this for the anniversary of the 25 January revolution," Egyptian Interior Minister Muhammad Ibrahim said.
He urged Egyptians not to be afraid to go to events marking the anniversary. However, earlier this week he warned supporters of the Brotherhood that any attempt to "disrupt" festivities will be dealt with "firmly."
In the most high-profile attack on Friday, a car bomb exploded at a security compound in central Cairo early in the morning and killed at least four people, including three policemen, security sources said.
They said the blast was the work of a suicide bomber. But footage broadcast on an Egyptian television channel showed a man getting out of a van and moving into another vehicle. Minutes later the van exploded.
Another blast in the Dokki district killed one person. An explosion near a cinema on the road to the Pyramids of Giza on the outskirts of Cairo also led to one fatality.
Clashes in the capital and several other cities between Mursi supporters and security forces which killed 11 people also raised tensions in the biggest Arab nation.
There was no immediate claim of responsibility for the car bomb attack in the parking lot of the Cairo Security Directorate, or the other blasts. But they had all the trademarks of attacks carried out by militants seeking to topple the army-backed government.
[Al-Arabyia]
