A reported bomb blast at a presidential campaign rally for Egypt’s former army chief Abdel-Fattah el-Sisi has injured at least four people.

The late Saturday incident in the Ain Shams district of the capital, Cairo, came as an explosive device was reportedly thrown near a press conference held by the presidential campaign staff of the ex-general who engineered the military coup against Egypt’s first freely-elected president, Mohamed Morsi, in July 2013.

According to a “security source” cited in a report by Egyptian Al-Ahram news website, an unidentified assailant threw the device into the audience of the campaign event as it was concluding.

A police officer, a low-ranking policeman and the security coordinator of the press conference were among those injured in the attack.

Presidential election is scheduled to take place in Egypt on May 26-27.

The only two candidates in the polls are Sisi and leftist politician, Hamdeen Sabahi, both of whom are fervent opponents of the Muslim Brotherhood, which rallied the nation to bring Morsi to power in Egypt’s first democratic elections in 2012.

Despite a brutal crackdown on the Brotherhood and Morsi supporters by the military-installed interim government, protests and violence continue across the country.

Last week, unidentified suspects set fire to the Sisi campaign headquarters in Sharqiya governorate.

Unidentified groups have also set fire to his campaign headquarters in Cairo and other governorates.

Sisi recently claimed to have survived two assassination attempts since the Morsi ouster.

Frequent explosions have struck towns near Cairo, as well as in the Nile Delta and the Sinai Peninsula since July 2013.