Washington: A US budget official told the Pentagon to "hold off" on military aid to Kyiv, 90 minutes after a controversial phone call between President Donald Trump and his Ukrainian counterpart Volodymyr Zelensky, according to an internal email.

The email was part of a series published by the investigative non-profit Center for Public Integrity. Trump is accused of withholding $400 million in assistance to Ukraine to push Kyiv to investigate his political rival, Joe Biden.