A large bomb exploded early Thursday near a national security building in a residential neighborhood in Cairo, Egyptian security officials said.
AP reported at least six people including at least one police officer, while another report quoting a local source said up to 24 people were injured, including six police officers.
The blast occurred in shortly before 2 a.m., tearing through a local office of the government's national security force and ripping down part of the building's facade, according to a person with knowledge of the episode who asked for anonymity to discuss a sensitive security matter.
There were no immediate reports of deaths from the explosion. 7For blocks around the blast site in the popular Shubra el-Kheima neighbourhood, glass from blown-out windows could be seen on the street.
A new anti-terrorism law was finalised this month amid a wave of attacks and killings this summer, including the assassination of Egypt's attorney general by a car bomb in Cairo.
The far-reaching new law sets a sweeping definition for who can face a harsh set of punishments, including journalists who don't toe the government line.
The Cabinet approved the draft law last month, two days after a car bomb in an upscale Cairo neighborhood killed the country's prosecutor general, Hisham Barakat. On the day it was approved, Islamic militants launched a multi-pronged attack attempting to seize a northern Sinai town, hitting the military with suicide attacks and battling soldiers for hours.
Inside his ruined clinic next door to the security building, plastic surgeon Gawad Mahoud lamented the Egypt's troubles.
"We were here painting the office, and then it went off. It was like an earthquake, it blew the doors off and smashed all the windows in," he said.
The bomber got out of the car and escaped on a motorcycle right before the explosion, the person added. There was no immediate claim of responsibility for the attack.
The blast was felt across the capital, rousing people from sleep and disrupting late-night gatherings.
Video broadcast by CBC, an Egyptian news channel, showed the bare white security building, its windows blown out and its face shorn off with rubble in the street.
Egypt has grappled with a growing insurgency in the two years since the military removed President Mohammed Morsi of the Muslim Brotherhood from power. Each new attack has chipped away at Egyptians' sense of security and claims by Al-Sissi's government to have gained the upper hand over the militants.