The first batch of South Korean survivors from a suspected terrorist attack in Egypt returned home Wednesday, three days after the bombing killed four people aboard a tourist bus.

The bus was carrying 31 South Korean tourists along with Korean and Egyptian tour guides in Egypt's bustling tourist destination of Sinai Peninsula when an identified man boarded the bus and detonated explosives in an apparent suicide attack.

The attack killed three South Koreans and the Egyptian bus driver. The bomber was reportedly also found dead.

Of the survivors, 15 who were not hurt or sustained minor injuries arrived at Incheon International Airport, west of Seoul, after traveling through Israel and Turkey.

While undergoing a health check-up at the airport, one of the survivors, 57-year-old Cha Ki-ho, said he heard a large "bang" on the bus at the time of the attack.

"I dropped my head at the sound and then as I tried to leave the bus, I heard what sounded like a gunfight outside the bus," he told Yonhap News Agency. "I don't know if someone boarded the bus with a bomb because I didn't see."

The South Koreans were from the same Christian church in the central South Korean city of Jincheon and had traveled to Egypt on a group pilgrimage.

The other 15 survivors who are being treated for their injuries at a hospital in Egypt will return home on Friday, officials said.

It remains unclear, however, whether two of them will be able to make it back as scheduled because they are due to undergo surgery there, they added.

It's also uncertain whether the bodies of the three South Korean victims will come with the second batch of survivors as talks are still under way with the Israeli and Egyptian governments to arrange their transfer.

An al-Qaida-inspired group called Ansar Beit al-Maqdis has claimed responsibility for the Sunday attack, but the Egyptian government is still investigating who is to blame.

"It's still not clear whether the group is behind (the attack), but (the South Korean foreign ministry) is taking steps to contact all South Koreans traveling or staying in the region and advising them to leave," a ministry official said on condition of anonymity.

The move follows a message posted Monday on a Twitter account reportedly affiliated with the terrorist group, which warned that any foreign travelers in Egypt could be the next target of an attack if they do not leave the country in four days. (Yonhap)