US president Donald Trump has called for the whistleblower to testify in person. Photograph: Chip Somodevilla/Getty Images

The impeachment investigation into president Donald Trump entered a new phase on Monday as House Democrats published full transcripts of the depositio(...)

Fiona Hill, US president Donald Trump’s former adviser on Russia and Europe, arrives on Capitol Hill on Monday to meet behind closed doors with House investigators. Photograph: Erin Schaff/The New York Times

A former senior adviser to US secretary of state Mike Pompeo will testify before three House of Representatives committees on Wednesday as the impeach(...)

Rudy Giuliani, President Donald Trump’s personal lawyer: The testimony revealed in a powerful way just how divisive his efforts to extract damaging information about Democrats from Ukraine were within the White House.  Photograph:  Erin Schaff/The New York Times

The effort to pressure Ukraine for political help provoked a heated confrontation inside the White House last summer that so alarmed John Bolton, then(...)