An improvised bomb had gone off Wednesday afternoon outside Cairo University, injuring 11 people including several security forces, Al-Ahram Arabic news website reported.

The explosive device had detonated near a faculty building across the street from the main university campus in Giza, the site of a previous deadly bombing.

Six police officers and four civilians were injured and transferred to hospitals, the interior ministry said in a statement. But the health ministry later said the injury toll had increased to 11.

Prosecutors said the perpetrators likely used a mobile phone to detonate the explosive device, Al-Ahram added.They said that the bomb was placed in a gas pipeline and was clearly aimed to target policemen stationed across from the university.

Cairo University, along with other campuses nationwide, has been a scene of unrest since the start of the new academic year two weeks ago, with recurrent clashes occurring between police and alleged Islamist students protesting against the government.

Police forces are stationed to secure universities from the outside, but they enter university grounds on occasion in order to quell on-campus protests. Falcon, a private security company, has been charged with securing the entrances of Cairo University among 15 other public universities nationwide.

There was no immediate claim of responsibility for Wednesday's bombing.

In April, a series of consecutive explosions took place at the same spot outside Cairo University, killing a senior police officer and wounding five other security personnel.

Over a week ago, a homemade bomb exploded near the Supreme Court in downtown Cairo, wounding 12 people.

Last month, a bomb blast hit near Egypt's foreign ministry headquarters, also in central Cairo, killing two policemen and ending a months-long lull from deadly attacks in the capital. The attack was claimed by a jihadist group called Ajnad Misr (Soldiers of Egypt.)

Egyptian authorities have been battling a mounting insurgency, based in the border Sinai Peninsula, since the ouster of president Mohamed Morsi in July 2013.

Militant attacks have killed hundreds of police and army troops, but civilians have also died in the violence.