Cairo: A bomb went off early Saturday under a bridge in the Egyptian capital, injuring three people, the official Middle East News Agency reported.

The blast was caused by a home-made bomb under Ghamra Bridge in central Cairo, Major General Sami Yousuf, the chief of the Civil Defence Department, told the agency.

“Cleaning workers in the area had found a strange object. When they tried to examine it, it exploded,” he added.

Last month, 13 people were injured in a bomb explosion near a courthouse in central Cairo.

Egypt has experienced a series of attacks targeting mainly security forces since the army deposed Islamist president Mohammad Mursi in mid-2013.

Last week, 30 soldiers were killed in a sophisticated attack on an army checkpoint in North Sinai, the deadliest assault since Mursi’s overthrow.

The raid prompted Egyptian authorities to declare a state of emergency in North Sinai and evacuate residents of an area near the border with the Palestinian Gaza Strip to set up a buffer zone there.

The government has repeatedly blamed the violence on Mursi’s Muslim Brotherhood and declared it a terrorist organization.