WILMINGTON, Del. (AP) — President Barack Obama says the United States will offer any assistance possible to determine what happened to a downed passenger jet in Ukraine and why.

Obama says the incident looks like it may be a terrible tragedy. He says the U.S. is working to determine whether any American citizens were on board. Obama says that’s the first priority for the U.S.

He says the nation’s thoughts and prayers are with the victims, regardless of where they are from.

Obama spoke during an event about transportation funding in Delaware. He discussed the plane incident earlier Thursday in a phone call with Russian President Vladimir Putin.

A Ukrainian official says a passenger plane carrying 295 people was shot down Thursday over eastern Ukraine.

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