A key witness in the House impeachment inquiry into President Donald Trump says that Vice President Mike Pence was informed about concerns that military aid to Ukraine had been held up because of the investigations.

Ambassador Gordon Sondland is testifying Wednesday publicly. He already appeared behind closed doors.

He tells lawmakers that Trump was supposed to meet Ukraine’s new leader Sept. 1 in Warsaw, Poland, but Trump couldn’t make it because of a hurricane in the U.S. so Pence attended instead.

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Sondland said he told Pence before the meetings that he had concerns that the delay in military aid to Ukraine had become tied to the issue of investigations.

President Volodymyr Zelenskiy raised the issue of security aid to Pence. But he didn’t specifically mention whether the idea of the hold-up was related to investigations.

Pence has denied that he knew about a link between military aid and the investigations