Egypt was on Friday mediating a potential ceasefire between Israel and Hamas, which controls the Gaza Strip, after a flare-up of violence across the border.

"There are continuing Egyptian efforts to return calm to the Gaza Strip, but no agreement has been reached yet," a Hamas official told AFP, on condition of anonymity.

A bomb blast in a train and clashes between protesters and security forces rocked Egypt on Thursday, as police quashed demonstrations marking the anniversary of Islamist president Mohamed Morsi's ouster.

The violence came as the pro-Morsi Muslim Brotherhood-led Anti-Coup Alliance issued an aggressive rallying cry demanding a "day of anger" to mark the occasion.

Egypt's military said troops killed 17 jihadists in shoot-outs in the restive Sinai Peninsula Thursday, the anniversary of the ouster of president Mohammed Morsi.

It said another three were arrested and that troops destroyed four vehicles belonging to jihadists in Rafah, on the border with the Palestinian Gaza Strip.

Egyptian police on Thursday 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.

A limited explosion occurred late Wednesday inside a car near a Cairo military hospital, Egypt's interior ministry said, hours before the first anniversary of deposed president Mohamed Morsi's military ouster.

Police arrested one of two men who were in the car while the second managed to escape, interior ministry spokesman Hani Abdel Latif told Agence France Presse, adding that the cause of the blast was still unknown and there were no casualties.

An Egyptian court on Wednesday sentenced a son of deposed Islamist President Mohamed Morsi and one of his friends to a year in prison each for possession and use of hashish.

Abdullah Morsi, 19, and his friend were arrested on March 1 after allegedly being found in possession of two hashish joints while they were in a car parked by the roadside in Qalyubia province, north of Cairo.

Egyptian police arrested Wednesday four members of an Islamist militant group over bomb blasts near a presidential palace, although another group claimed it had planted the explosives.

Separately, the interior ministry said police arrested two people over bombings at Cairo metro stations on June 25 that wounded five people.

Two Egyptian police officers were killed defusing bombs near the presidential palace in Cairo Monday, almost a year to the day after a military takeover unleashed a wave of repression and militant attacks.

An Islamist militant group, one of several that have spearheaded attacks since President Mohammed Morsi's ouster on July 3 last year, warned several days ago that it had planted bombs in the vicinity of the east Cairo palace.

An Egyptian and two Israelis, including an intelligence officer, will be tried by an Egyptian court for allegedly "spying" for Israel, judicial sources said on Sunday.

The Egyptian is in custody and the two Israeli "fugitives" are to be tried in absentia, the sources said. The date of the trial has yet to be fixed.

Gunmen killed four Egyptian policemen in the restive northern Sinai on Saturday, a security source said, with police blaming the attack on "takfiri" jihadist militants.

Militants in the Sinai Peninsula have stepped up attacks on troops and police since the military ousted Islamist president Mohammed Morsi last July.