A pipeline carrying gas from Egypt to Israel and Jordan has exploded after an attack by an armed gang in the north Sinai area of Egypt.
A tower of flames shot into the air and forced the pipeline to be shut down, Egyptian security officials say.
It is the second such attack in a month on the pipeline, south of the town of el-Arish, just 30 miles (50km) from the border with Israel.
On that occasion, when gunmen planted explosives, they failed to detonate.
"An unknown armed gang attacked the gas pipeline," an unnamed security source told Reuters, adding that the flow of gas to Israel and Jordan had been hit.
Neighbouring Jordan depends on Egyptian gas to generate 80% of its electricity while Israel gets 40% of its natural gas from the country. Syria also imports gas from Egypt.
Any disruption would force Jordan to rely on more expensive diesel fuel.
The valves controlling the flow of gas from the main terminal in Port Said, on the Mediterranean coast, were shut down to dampen the flames and people living nearby were forced to leave their homes.
However, there have been no reports of casualties.
The pipeline has frequently been targeted, including an attack on 5 February during the uprising that forced Hosni Mubarak from power. On that occasion, gas exports to Israel and Jordan were stopped for a month.
The area is home to Bedouin tribesmen who have often complained of being neglected and oppressed by the central government. Tribesmen attempted to sabotage the pipeline in July 2010, AP reports.
The main road in the area was temporarily closed by tribesmen on Tuesday but then reopened by the army, Egypt's Mena news agency reported.
Egypt began supplying Israel with gas in 2008 under a 20-year deal.
But a former head of Israel's Mossad intelligence service, Danny Yatom, said Israel now should focus on developing its own offshore gas reserves.
"We need to understand that this is a problem we're going to live with for a very long time, and we need to start preparing an alternative now," he told Israeli radio.
There is widespread opposition to the deal in Egypt because of Israel's blockade of the Gaza Strip.
There has also been a lengthy legal battle to ban supplies to Israel, amid claims that the gas was being sold at preferential rates. A ban was imposed by a court then overturned by the Supreme Court last year, though it was never enforced.