A fatal blast during a protest against Egyptian President Mohammad Mursi in the Suez Canal city of Port Said was caused by a home-made hand grenade, security sources said Saturday.
After the blast late on Friday, which killed one man, traces of an explosive substance were found on the bodies of some of the 15 wounded. Ballistics tests were still under way.
Hundreds of anti-government protesters had gathered in central square in the city, at the Mediterranean end of the canal, one of several small demonstrations around the country ahead of mass rallies on Sunday aimed at unseating Mursi.
The chairman of the Suez Canal Authority said on Saturday that canal authorities were coordinating with the armed forces and security and intelligence agencies to secure the key global waterway.
Traffic of ships and cargo through the canal remained normal, he said.
Cities around Suez have already been flashpoints for violence this year, causing minor stoppages through the canal.
Egypt protest blast was due to explosive device