A bomb has exploded near Egyptian troops working to demolish houses along the border with the Gaza Strip, causing no casualties but prompting authorities to raise security alert levels in the area.
The border town of Rafah and its surrounding areas in the northern part of the Sinai Peninsula have been under a state of emergency for more than a week since an October 24 militant assault killed 31 troops.
It was the deadliest attack on Egyptian troops in recent times.
No one claimed responsibility for the bombing, but the Northern Sinai has become a stronghold of Islamic militants who have carried out scores of attacks in recent months, mainly targeting soldiers and police.
Despite a nearly yearlong military offensive, the insurgency has expanded at times to reach Cairo and other cities.
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Following the killing of the 31 troops, the government declared it will create a 500-metre buffer zone along Egypt's 13-kilometre border with Gaza extending from the Mediterranean Sea.
Over the past week, troops have demolished 300 houses out of more than 800 targeted, home to more than 10,000 residents.
Speaking on Monday, President Abdel-Fattah el-Sissi said the military is capable of dealing with the threat of the militants, though it had wanted to avoid shedding blood.
"We don't want the military to enter a confrontation with anyone. We want to protect Egyptian lives," el-Sissi said.
"The military has been patient and put up with much."
Authorities had also imposed a dusk-to-dawn curfew and on Monday limited the movement of armoured vehicles and tanks on main roads around Rafah believed to be booby-trapped with roadside bombs, the officials said.
