CAIRO -- A bomb placed under a nearby car exploded Saturday in the coastal city of Alexandria as the city security chief's convoy passed by, killing two policemen and wounding four others, the Interior Ministry said. Local media reports said Gen. Mostafa al-Nimr survived the explosion and he was seen on a local TV channel in good condition while inspecting the area of the blast shortly after it took place.

The Interior Ministry had earlier reported only one policeman killed in the blast which occurred in the vicinity of a police station in the city's central Roshdi district.

Health Ministry spokesman Khaled Megahed told The Associated Press that two policemen were killed and four others wounded in today's explosion, adding that one civilian was also wounded.

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No group immediately claimed responsibility for the attack.

Residents close to the clean said they heard a loud blast Saturday morning.

"I suddenly heard a very strong explosion and ran towards the street, but I retreated out of fear," Mohamed Ismail told Reuters news agency. "I thought the building would collapse and kept checking on its pillars."

Egyptians gather around a burning vehicle at the site of a bomb attack in the northern port city of Alexandria, which hit a convoy of the city's security chief, on March 24, 2018. AFP/Getty

The attack comes just days ahead of Egypt's presidential election, in which President Abdel-Fattah el-Sissi is virtually certain to be re-elected. It also comes during a massive security operation involving land, sea and air forces in areas covering north and central Sinai and parts of Egypt's Nile Delta and the Western Desert, along the porous border with Libya.

The Interior Ministry said the explosive device had been placed under a car and it detonated as the convoy passed by.

State-run MENA news agency said the public prosecutor has ordered an investigation into the incident.

Egypt has for years been struggling to contain an insurgency spearheaded by a local affiliate of the extremist Islamic State of Iraq and Syria (ISIS) in the turbulent Sinai region but attacks on the mainland have also occurred.

The country has been under a state of emergency since April 2017, when suicide bombings struck two Coptic Christian churches in Alexandria and Tanta on Palm Sunday in an attack claimed later by the Islamic State group.