Four police personnel were injured in a bomb blast in Cairo on Thursday afternoon, Al-Ahram Arabic news website reported.

The explosion took place near a security checkpoint in the vicinity of Helwan University, on the southern outskirts of the city, causing injuries to three officers and a low-ranking official.

Explosives experts and police have arrived at the site to investigate the incident.

The blast occurred shortly after a sound bomb went off at a major railway station in Ramsis Square, downtown Cairo.

Numerous attacks on police personnel have taken place in recent months.

Cairo University has been the site of two blasts. On 22 October, a bomb went off outside the university campus, injuring six police officers and four civilians.

On 2 April, a policeman was killed and at least five injured in a bomb attack outside the university.