A bomb tore through a bus carrying South Korean tourists near an Egyptian border crossing with Israel yesterday, killing at least four people and wounding 13.
It was first attack on tourists since the removal of Islamist president Mohammed Mursi in July sparked unrest and a spate of attacks across the country.
The bomb went off in the front section of bus carrying the tourists at Taba border crossing with Israel in south Sinai, the interior ministry said, adding that one of those killed was the Egyptian driver.
Health ministry spokesman Ahmed Kamel said four people were killed in the explosion and 13 were injured. The bomb peeled off the front of the yellow bus and tore out parts of the roof.
A witness who had been waiting for a bus nearby described scenes of horror as the bomb ripped through the vehicle.
"There were body parts and corpses. I saw the corpse of a man who appeared to be Korean, with a leg missing," said the witness, Ahmed Ali, a doctor who runs a clinic in a neighbouring resort.
"This is a terrorist act that was carried out with an explosive device," said an army source. "Terrorist" is the word used by security officials to describe Islamist militants.
The interior ministry said the tourists had set off from Cairo and were waiting at the crossing to enter Israel when the explosion took place.
A spokesman for the Israel Airports Authority, which is responsible for border security, said the Taba crossing had been closed in the wake of the blast.
No one immediately claimed responsibility for the attack.
If militants were behind yesterday's attack, it would mark a shift in strategy to attacking tourists and economic targets and not just police and soldiers in Egypt, the Arab world's biggest nation.
The unrest has severely hit tourism, a vital earner in Egypt, which has been targeted sporadically by militants over the past two decades.
The government's census agency said the number of tourists was down in December 2013 by almost 31 percent compared with the same month in 2012.
Tourism Minister Hisham Zaazou said he was "very disappointed" by the attack, which revived memories of an Islamist insurgency in the 1990s.
"I hope this will be an isolated incident that will not reoccur. I'm reassuring that all the rest of the country is safe and secure and what happened can happen anywhere in the world," Zaazou said.
The military-installed government has accused Mursi's Muslim Brotherhood of masterminding the attacks that have also targeted police headquarters in Cairo. The Brotherhood, now designated as a terrorist group, denies its involvement.
The deadliest attacks have been claimed by the Sinai-based Ansar Beit al-Maqdis group, whose leadership is drawn from militant Bedouin who want an Islamist state in the peninsula.
The group also took responsibility for downing a military helicopter in Sinai on January 25 using a heat-seeking shoulder-fired missile.
"The militants in Sinai are now looking for soft targets, without entering confrontation with police and armed forces who have taken precautions," said Mustapha Kamel Al-Sayid, a professor of political science at Cairo University.
"This is a cheap win for them without a high risk."
While the government has succeeded in driving the Muslim Brotherhood underground with a security crackdown, it is struggling to cope with increasing pressure from militants in the Sinai, where several army offensives have failed to root them out.
Between 2004 and 2006, scores of Egyptians and foreign tourists were killed in a spate of bombings in resorts in south Sinai.
In 1997, Islamist militants massacred dozens of tourists in a pharaonic temple in the southern city of Luxor.
Agence France-Presse, Reuters