Six Egyptian soldiers have been killed in a drive-by shooting near Cairo shortly after a massive bomb hit security headquarters in a town near the area's tourist resorts in southern Sinai, killing at least two and wounding dozens.
The attacks came a day after dozens were killed when holiday celebrations marking the start of the 1973 Middle East war turned into deadly clashes across Egypt, though it was not clear if the violence was related.
The six soldiers were on patrol in a pickup truck when masked gunmen in another vehicle opened fire at them in an area west of the Suez Canal city of Ismailia.
The explosion at the security headquarters in the town of el-Tor killed two people and wounded nearly 50, signalling what could be the spread of attacks by Islamic militants, already active in northern Sinai.
Daily attacks against security forces in the volatile northern Sinai Peninsula have increasingly resembled a full-fledged insurgency. But the region of southern Sinai, which includes the popular diving resort of Sharm el-Sheikh, has been mostly quiet since a series of deadly attacks in 2005 and 2006.
The four-storey building sustained serious damage and security sources said the blast was probably a car bomb detonated by remote control.
A day earlier at least 51 people were killed in clashes between security forces and supporters of ousted Islamist president Mohammed Morsi across much of Egypt.
At least 40 of those killed were in Cairo, where some neighbourhoods saw hours of pitched street battles between police and protesters. The fighting left streets looking like combat zones, with fires burning, black smoke rising and the air thick with tear gas.
That death toll and the new attacks constituted the latest chapter in the turmoil rocking Egypt since the ovethrow in February 2011 of Hosni Mubarak.
The latest violence is certain to set back efforts by the interim, military-backed government to revive the economy, especially the vital tourism sector, and bring order to the streets of Cairo, where crime and lawlessness have been rife.
Mr Morsi was Egypt's first civilian and first freely elected president, succeeding four since the early 1950s who hailed from a military background. But after a year in office, he was faced by massive protests accusing his Muslim Brotherhood of taking over power - and on July 3, military chief General Abdel-Fattah el-Sissi removed him.
The military is now back as the real source of power in Egypt, and state and independent media have been depicting it as the country's saviour - with growing calls for el-Sissi to run in the presidential election due early next year.