WASHINGTON (AFP) - House Democrats subpoenaed Secretary of State Mike Pompeo for Ukraine-related documents on Friday (Sept 27) as they plunged into an impeachment probe of President Donald Trump.

The heads of three House committees gave Pompeo one week to produce the documents, saying multiple State Department officials have direct knowledge of the matters involved in the impeachment inquiry.

"The Committees are investigating the extent to which President Trump jeopardised national security by pressing Ukraine to interfere with our 2020 election and by withholding security assistance provided by Congress to help Ukraine counter Russian aggression," they said.