EL-ARISH, Egypt -- A suicide bomber and roadside explosives targeting police and military in northeastern Egypt's restive Sinai Peninsula killed two and wounded 46 early Tuesday, security officials said. In a city south of Cairo, two suspected militants died when a bomb they were carrying on a motorbike exploded.

Egypt has battled a burgeoning insurgency in northern Sinai for years but attacks against army and police there have dramatically increased since the 2013 ouster of Islamist President Mohammed Morsi. The military has carried out an extensive offensive against militants in the region, declared a state of emergency and a dusk-to-dawn curfew. Authorities also demolished houses near the Gaza border to combat trafficking of arms and jihadists through underground tunnels.

In the first attack, the suicide bomber drove a stolen water tanker packed with explosives to the police compound in el-Arish city. His refusal to slow down at the gate prompted police to fire at the vehicle, setting off the explosives inside, the officials said, speaking on condition of anonymity because they were not authorized to talk to media.

A civilian passer-by, a driver for the nearby electricity company, was killed. Most of the policemen were wounded by shrapnel.

Later, Interior Ministry spokesman Hani Abdel-Latif said the bomber was trying to reach a nearby hotel where a large number of police officers reside.

Shortly after, an army officer was killed and three soldiers wounded when suspected militants blew up their armoured vehicle using roadside explosives a few kilometres (miles) from the site of the first bombing, officials said.

Apart from Sinai, smaller attacks and bombings in Cairo and other cities across Egypt have raised fears ahead of a major economic conference later this week aimed at attracting foreign investments.

Two suspected militants were killed in Fayoum, a city southwest of Cairo, on Tuesday when an explosive device they were carrying on a motorbike detonated, officials said. One of the men was wanted for a previous attack on a police station in Fayoum, the officials said, speaking on condition of anonymity because they were not authorized to talk to media.

Fayoum is a hotspot of anti-government demonstrations by supporters of Morsi and the banned Muslim Brotherhood. They denounce the deaths of hundreds of Islamists at the hands of security forces when pro-Morsi camps were dispersed in Cairo in August 2013. Thousands have been detained.

Ansar Beit al-Maqdis -- a Sinai-based group which has pledged allegiance to Islamic State group leader Abu Bakr al-Baghdadi -- has claimed responsibility for most of the major attacks while smaller militant groups claimed responsibility for smaller attacks.

On Sunday, Brig. Gen. Mohammed Samir, the official spokesman of the armed forces, said Egyptian troops and helicopter gunships have killed 70 militants in northern Sinai in the first week of March, arrested 23 suspects and seized a large number of weapons and ammunitions. It was not possible to verify his account. Locals say most of the slain men are residents, not militants.