US President Donald Trump speaks to reporters before leaving the White House in Washington D.C. Sept. 12, 2019. (Photo by Ting Shen/Xinhua)

Gordon Sondland, the US ambassador to the European Union, is expected to testify next week before the House committees investigating US President Donald Trump and Ukraine, Axios reported on Thursday, citing three congressional sources.

On Tuesday, the State Department had ordered Sondland, a major Trump political donor, not to appear at a closed-door meeting of three US House panels investigating Trump.