A bomb blast in a train in the Egyptian city of Alexandria on Thursday wounded five people, security officials said, according to AFP.
According to the report, the bomb, which was hidden in a briefcase near a passenger seat, exploded inside a train compartment.
The attack as Egyptian police swiftly quashed Islamist protests marking the first anniversary of the military ouster of president Mohammed Morsi, firing tear gas and arresting dozens of demonstrators.
The protests were seen as a test of the Islamists' strength, with the Muslim Brotherhood-led Anti Coup Alliance having issued an aggressive rallying cry demanding a "day of anger" to mark Morsi's overthrow.
Police closed off several main squares in Cairo and scoured neighborhoods to head off protests, AFP reported.
In Cairo's Ain Shams district, black-clad riot policemen fired tear gas and shotguns to disperse a few dozen protesters who burned tires on a road.
Police also dispersed other protesters elsewhere in the capital, security officials told AFP.
39 wanted activists were arrested ahead of Thursday's protests, and 157 allegedly illegal demonstrators were detained during the day, the interior ministry said.
Morsi's Muslim Brotherhood movement was listed as a terrorist group after his overthrow last July 3 and many of its leaders, including Morsi himself, have been jailed.
The ex-army chief who toppled him, Abdel Fattah al-Sisi, has since replaced him as Egypt's elected president.
Security forces were also on high alert Thursday for further bombings, days after two senior policemen were killed when devices they were defusing outside the presidential palace exploded.
Since Morsi's ouster after a turbulent year in power, at least 1,400 people, mostly his Islamist supporters, have been killed in street clashes and more than 15,000 have been imprisoned.
Despite the crackdown, the Islamists have insisted on continuing their protests with the aim, they say, of making Egypt ungovernable for Sisi.