A federal judge has ruled that White House staff can be made to testify before Congress, rejecting the Trump administration's claims of immunity.
A top US diplomat has told an impeachment inquiry that he followed President Donald Trump's orders to put pressure on Ukraine to investigate his Democratic rival, Joe Biden.
U.S. House Speaker Nancy Pelosi is amplifying her unfavorable comparison of President Donald Trump to fellow Republican Richard Nixon, saying that disgraced president at least cared enough about the country to leave office before his impeachment.
An overheard phone call takes centre stage in impeachment inquiry against the US president.
A top US diplomat says President Trump made the release of military aid to Ukraine conditional on a pledge that a political rival would be investigated. Ambassador Bill Taylor testified before an impeachment inquiry that he was told Mr Trump wanted Ukraine to probe ex-Vice-President Joe Biden's dealings.
A parade of U.S. diplomats will head to Capitol Hill for closed-door testimony this week as Democrats build their impeachment case against President Donald Trump, while the White House considers ways to slow down the process.
Texts released by Democrats in Congress reveal how US officials worked to push the Ukrainian president into opening a public inquiry into President Trump's leading opponent, Joseph Biden.
Democratic calls to impeach President Donald Trump are gathering pace after it emerged he withheld aid to Ukraine, pressing it to investigate his would-be White House challenger Joe Biden.