WASHINGTON, July 17 – President Barack Obama directed U.S. officials on Thursday to do all they could to support an investigation into what caused a Malaysian jetliner to crash in a Ukrainian war zone and pledged support to the affected countries as the probe moves forward, Reuters reported.

Obama went ahead with a trip to tout infrastructure investment in Delaware and to raise money for Democrats in New York despite the incident in which more than 290 people were killed. A Ukrainian official said there were 23 Americans aboard but U.S. officials did not confirm that.