Malaysia Airlines MH17 crash: Obama calls it 'terrible tragedy'; jet was flying normally until crash

WILMINGTON (Reuters) - US President Barack Obama said on Thursday the crash of a Malaysian jetliner on the border of Ukraine was a "terrible tragedy" and the United States would offer any assistance necessary to help determine what happened and why.

Mr Obama said officials were looking into whether US citizens were on board the plane. He made the comments at the beginning of remarks about infrastructure in Delaware.

The Malaysian airliner which came down in eastern Ukraine on Thursday was flying normally without problems until it disappeared from radar, the head of Ukraine's airspace regulatory body said.

"The flight was taking place normally ... There had been no word of any problems from the crew," Mr Dmytro Babeychuk said at a news conference.