CAIRO, May 18 (Xinhua) -- Four people were injured on Saturday night when an improvised explosive device went off during a rally supporting Egypt's presidential candidate Abdel Fattah El-Sisi in eastern Cairo, state-run al-Ahram newspaper reported Sunday on its website.
An official security source confirmed that two citizens, a police officer and a policeman suffered minor injuries in the explosion in Ain Shams area of Cairo, and that the area was secured by police forces soon after the incident, where no other explosive devices were found.
The device was thrown into the pro-Sisi crowd by an unidentified individual, according to Ahram.
Random acts of violence have escalated as presidential election set for May 26 and 27, with leftist leader Hamdeen Sabahy and former military chief Abdel Fattah El-Sisi competing to win the race.
The vote for the Egyptian expatriates kicked off last Thursday and it will continue until Monday.
El-Sisi, the more widely popular presidential candidate, claimed recently that he was targeted in two assassination attempts. Also, one of his campaign offices was set on fire by unidentified suspects last week as well as his Cairo headquarters and other premises in other governorates earlier.
Security officials announced that pro-Muslim Brotherhood members were mostly behind the violent attacks due to the ouster of Islamist president Mohamed Morsi last July by the military.
Since then, a wave of explosions have targeted security men and their premises in the restive Sinai Peninsula and they lately extended to hit the capital, the Nile Delta cities and other provinces across the country.