U.S. Ambassador to the European Union Gordon Sondland arrives to testify behind closed-doors as part of the House of Representatives' impeachment inquiry into President Donald Trump on Capitol Hill in Washington, U.S., October 17, 2019. REUTERS/Carlos Jasso

WASHINGTON (Reuters) - A second staffer for the U.S. Embassy in Kiev overheard a phone call between President Donald Trump and the U.S. envoy to the European Union, in which the need for Ukraine to conduct “investigations” was discussed, the Associated Press reported on Thursday, citing an unnamed source briefed on the situation.

On Wednesday, the top U.S. diplomat in Ukraine, William Taylor, disclosed the previously unknown July 26 call in public comments during Congress’ first televised hearings amid lawmakers’ impeachment inquiry.