Malaysia jet crash: President Barack Obama pledges US help

US President Barack Obama has said his thoughts and prayers are with the families of those on board a Malaysian airliner which crashed in the east Ukraine conflict zone carrying 295 people.

"The US will offer any assistance we can, to help determine what happened and why," he said.

There are fears a missile attack may have brought down the plane, which had been en route from Amsterdam to Kuala Lumpur.