Impeachment hearing witness: 'I was concerned by the call'
Lt Col Alexander Vindman testified to Congress about his concerns over the "improper" phone call between President Donald Trump and Ukraine's president.
The White House official and decorated army veteran gave the statement during the second week of public hearings in Trump's impeachment inquiry.
Mr Vindman listened to the phone call which sparked the impeachment inquiry against the US president. Trump denies any wrongdoing.