Gunmen attacked a gas pipeline In central Sinai on Friday. The gunmen caused an explosion of a natural gas pipeline supplying an industrial zone.
Nobody was hurt but the blast disrupted gas supplies to some factories in the area, security sources said.
Interim Prime Minister Hazem el-Beblawi condemned the attack on the pipeline and vowed to punish such crimes with force.
Throughout Egypt on Friday tensions blared, with at least two people were shot dead as clashes between Muslim Brotherhood supporters and police flared up across Egypt on Friday, state news agency MENA reported.
The violence erupted a day before Egyptian authorities are expected to announce official results of this week's referendum on a new constitution, part of an army-backed transition plan for the Arab world's most populous nation.
One man was killed by a gunshot to the neck in the city of Fayoum, south of Cairo, a local health ministry official told Reuters. Another man was shot dead in a district on the outskirts of Cairo, a judicial source said.
Supporters of the Brotherhood also clashed with security forces in the city of Suez, MENA reported, as well as in Ismailia and a number of locations in the capital, security sources said.
Egyptian security forces have arrested thousands and killed hundreds of Brotherhood supporters since the overthrow of Morsi, Egypt's first democratically elected leader, and last month they declared the group a "terrorist organization".
The Brotherhood, which says it is committed to peaceful activism, had unsuccessfully urged a boycott of the referendum on a new constitution.
State media, citing initial estimates, said around 95 percent of voters supported the new constitution, which would replace one approved under Morsi and would strengthen the state bodies that defied him: the army, the police and the judiciary.
In another sign of pressure on the Brotherhood, members of the engineers' union forced their head, identified as a Brotherhood supporter by state news portal Al-Ahram, to resign.
Unions have traditionally been seen as a gauge of Brotherhood support, in large part because the group was banned from politics during the Mubarak era. It lost its grip on another powerful professional union, representing doctors, in a vote last month.
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