Malaysian Prime Minister Najib Razak said on Friday he was shocked by reports a Malaysia Airlines plane had gone down over Ukraine and he was launching an investigation.
"I am shocked by reports that an MH plane crashed. We are launching an immediate investigation," Najib said on his Twitter feed. MH is the code for Malaysia Airlines.
The incident comes after a Malaysia Airlines plane went missing on March 8 on a flight from Kuala Lumpur to Beijing with 239 passengers and crew on board. It has not been found.
Najib was on his way to the operations centre at Kuala Lumpur International Airport, an official in his office said.
Malaysia Airlines said in a statement it had received notification from Ukrainian air traffic control that it had lost contact with flight MH17 at 1415 GMT, 30 km (18 miles) from the Tamak waypoint, approximately 50 km (31 miles) from the Russia-Ukraine border.
The Boeing 777 had left Amsterdam at 12.15 p.m. (Amsterdam time) and was expected to arrive in Kuala Lumpur at 6.10 a.m. (2210 GMT) on Friday, the airline said.
The airline said there were 280 passengers and 15 crew on board.
Writing by Robert Birsel