CAIRO - A bomb near an army intelligence building wounded four soldiers Sunday, the third such blast within a week after the Muslim Brotherhood's designation as a terrorist organisation further polarised Egypt.
The explosion, which the army called a "cowardly terrorist" act, comes as the military-installed authorities plan to hold a referendum on a new constitution next month, the first step towards democracy since the ouster of Islamist president Mohamed Morsi in July.
Sunday's blast in Sharqiya province in the Nile Delta destroyed the rear compound wall of the intelligence building, the army said, adding that four soldiers were wounded.
It was the third such attack in less than a week.
Another was averted on Sunday when experts defused a bomb near the front gate of Al-Azhar's medical faculty in New Damietta city north of Cairo, security officials said.
On Tuesday, a suicide car bomber killed 15 people at a police building in Mansoura, north of the capital. And on Thursday, a bomb in Cairo wounded five people on a bus.
The Mansoura attack, one of the deadliest since Morsi's ouster, triggered widespread outrage.
A day after that attack, which was claimed by Al-Qaeda-inspired jihadists, the authorities accused the Brotherhood of perpetrating it and listed the Islamist movement to which Morsi belongs as a "terrorist organisation".
But the Brotherhood, which prevailed in all elections since the ouster of strongman Hosni Mubarak in early 2011, said it is "innocent of any violent incident that has (been) or will be committed".