CAIRO -- An explosion tore through a bus filled with South Korean sightseers Sunday in the Sinai Peninsula, killing at least four people and raising fears that Islamic militants have renewed a bloody campaign to wreck Egypt's tourism industry.
The bombing near the tip of the Red Sea's Gulf of Aqaba was the first attack against tourists in Sinai in nearly a decade.
There was no immediate claim of responsibility. But the blast bore the hallmarks of attacks blamed on the al-Qaida-linked militant groups that have been battling government forces in Sinai's restive north for years.
At least three South Korean tourists were killed and 12 seriously wounded, according to Egyptian security officials. The Egyptian bus driver was also among the dead, the officials said.
Egypt's tourism sector, which normally accounts for about 11 percent of the economy and 20 percent of all foreign currency revenue, has been badly hit by the deadly turmoil that has roiled the country since the 2011 revolt that overthrew ruler Hosni Mubarak.
Sunday's blast came as signs of a slow recovery in the industry were emerging, especially at Red Sea resorts in Sinai like Sharm el-Sheik.
"The sad consequence for Egypt is that this takes the tourism industry and devastates it for years into the future," said Jon Alterman, director of the Middle East Program at the Center for Strategic and International Studies in Washington.
In Seoul, South Korea, the Foreign Ministry said in a text message that 31 passengers from a church in Jincheon were being led by a South Korean tour guide.
Sunday's bombing was the first attack against tourists in Sinai's southern region since a spasm of bloodshed in 2004-06 that killed about 120 people. That included a bombing at a luxury hotel in Taba in 2004 that left 34 people dead, 11 of them Israelis.
In a separate development Sunday, the office of Egypt's former chief of staff, Sami Annan, announced that the retired general will run for president in elections scheduled for April.
The decision apparently pits Mr. Annan against Field Marshal Abdel-Fattah el-Sissi, who led the military takeover that ousted Mr. Morsi. Marshal Sissi is widely expected to announce his candidacy, and is heavily favored to win.