Seoul: The pilot and co-pilot of an Asiana Airlines cargo plane were killed when the aircraft caught fire and crashed Thursday off South Korea's southern island of Jeju, officials said.
Investigations were focusing on whether inflammable material in the hold of the Boeing 747-400 sparked the blaze.
The plane left the country's main international airport at Incheon at 3:05am, bound for Shanghai's Pudong airport.
But about one hour after take-off the pilot radioed Chinese air traffic controllers in Shanghai that fire had broken out in the hold and that the plane had to divert to Jeju, transport ministry officials said.
Fire erupted
"In its last message, the crew told Shanghai traffic controllers that fire had erupted in the hold. We suspect some inflammable material caught fire there," Deputy Transport Minister Kim Han-Young told journalists.
The plane carried 58 tonnes of cargo, including 0.4 tonnes of potentially risky materials such as lithium batteries, paint, amino acid solution and synthetic resin, he said.
A coastguard patrol boat found debris including part of the wing, seats and a liferaft just over 100km west of the island.
Four coastguard boats and a helicopter are searching the area.
Heavy rain
South Korea has been lashed with extraordinarily heavy rain this week, with landslides and floods killing dozens and causing havoc. Kim said it was unclear whether the weather had caused any problems for the plane.
Coast guard officials said there was no rain in the area but stronger-than-normal wind.
Tense military standoff
North and South Korea are in a tense military standoff across their heavily armed border, but there was nothing to immediately indicate that the crash had any military connection.
Asiana Airlines was in the news last month when two South Korean marines fired rifles at an Asiana plane carrying 119 people.
South Korea's military later apologised, saying the marines mistook the plane for a North Korean military aircraft.
The military said it planned to strengthen training so troops can better distinguish civilian planes. Officials said the plane wasn't in range of the rifle fire.
