A bystander was killed on Tuesday when a roadside bomb exploded in Alexandria, Egypt's second largest city. Meanwhile, authorities defused two more explosive devices at Cairo International Airport.

The Associated Press reported officials said the Alexandria bomb was targeting a police patrol driving in the beachfront town of Agamy. It was apparently detonated remotely as the vehicles moved, thus injuring three civilians: a street peddler, his son and a bystander. The latter later died of his wounds and was identified as a 27-year-old man who had been walking in front of the city's Mabaret Al-Asafra Hospital.

The devices found in Cairo, meanwhile, were planted, respectively, at the airport's EgyptAir arrival hall and near a police patrol location in the facility's parking lot. They also appeared to be controlled remotely by cell phone, authorities said after the bombs were defused. Flight operations at Cairo International Airport were ot affected, officials added.

In a third incident, a flash-bang grenade planted inside an electrical box exploded in an open-air commercial arcade in downtown Cairo. The device caused no injuries.

Islamist militants have carried out numerous bomb attacks on soldiers and police since mid-2013, when Egypt's military removed President Mohamed Mursi, the country's first democratically elected leader, Reuters explained.

Mursi is a member of the Muslim Brotherhood, an organization that has since been outlawed and that army chiefs have compared to the ISIS and al-Qaida terrorist groups.

The Egyptian ISIS branch last week claimed responsibility for coordinated attacks in the Sinai Peninsula that killed more than 30 security personnel, the British news service detailed. ISIS, which refers to itself as the "Islamic State" and controls large swaths of land in Syria and Iraq, has recently expanded its operations to North African nations, including Libya and Egypt.

On Monday, an Egyptian court had sentenced 183 Muslim Brotherhood supporters to death over their alleged involvement in the killings of police officers. President Abdel Fattah al-Sisi, the army chief who has ruled the country since Mursi's ouster, has warned his countrymen to expect a long and hard crackdown on Islamist terrorism.