A car bomb has injured six policemen after exploding in front of a security building in Cairo, the latest in a wave of militant attacks that has rocked Egypt.
The powerful blast in northern Cairo's district of Shubra came in the middle of the night, at a time when Egyptian security forces are being targeted by an Islamic State insurgency.
"A man suddenly stopped his car in front of the state security building, jumped out of it and fled on a motorbike that followed the car," authorities said in a statement.
"The car exploded wounding six policemen."
The blast made a wide crater near the four-storey police building, shattered its windows and destroyed a major part of a surrounding wall.
One of the two guard posts at the entrance of the building was also destroyed.
A vehicle engine lay metres away from the entrance as police cordoned off the site to prevent crowds of people from gathering, and broken metal parts of a car lay scattered on the ground.
Front glass windows of three buildings near the site were also shattered.
"The front glass window of my apartment broke and two doors fell down. It was like an earthquake," said Hady Gad, a resident living behind the building.
The bombing comes just days after President Abdel Fattah al-Sisi ratified an anti-terrorism law, which critics claim gives wider powers to police, restricts human rights and muzzles the press.
No one has yet claimed responsibility for the blast, but Sinai Province, the Egyptian branch of the Islamic State group, has regularly carried out attacks on security services as part of its insurgency.
Islamic militants say their attacks are in retaliation to a police crackdown targeting Morsi supporters, which has left hundreds dead and thousands jailed.
Hundreds more have been sentenced to death after speedy trials, denounced by the United Nations as "unprecedented" in recent history.
Thursday's blast comes weeks after Islamic State claimed credit for a deadly car bomb attack in July, which targeted the Italian consulate in downtown Cairo.
That attack was the first targeting a foreign mission in Egypt since the jihadists began their campaign two years ago.
The consulate bombing was followed by the abduction and apparent beheading of Croatian engineer Tomislav Salopek, which the Sinai Province group claimed on August 13.