Egyptian authorities said they killed six people on Sunday in connection to a deadly car bombing that targeted the coastal city of Alexandria's security chief.

The blast occurred near the Tolip Hotel on Saturday in Rushdi, a neighbourhood in Egypt's second city, close to the motorcade of Major-General Mostafa al-Nemr, head of security in Alexandria. The attack killed two soldiers.

The interior ministry announced in a statement it discovered a "terrorist den" belonging to the outlawed Muslim Brotherhood's armed wing, the Hasam movement.

"The interior ministry has dealt an effective blow to the armed wing of the Muslim Brotherhood ... and exchanged fire with its elements, which led to the killing of six," the statement said.

The Hasam movement first emerged in 2016 when it claimed responsibility for a series of attacks on government officials.

The Muslim Brotherhood has said it rejects all forms of violence.

Saturday's attack came days before Egyptians head to the polls in elections that the incumbent, President Abdel-Fattah el-Sisi, is poised to win.

Several of Sisi's opponents were sidelined in the run-up to Monday's vote, most notably retired army chief Sami Anan and former Prime Minister Ahmed Shafik.

The election is widely expected to see Sisi easily better his only opponent, 66-year-old Mousa Mostafa Mousa, chairman of the liberal El-Ghad Party. Moussa is a Sisi loyalist who had previously endorsed the president.