The moved raised the stakes for the White House as Trump fights back to protect his presidency amid allegations he used the powers of his office to enlist Ukraine’s President Volodymyr Zelensky to find dirt on Democratic rival Joe Biden in exchange for military aid.

WASHINGTON (AFP) — Democrats in Congress asked US Vice President Mike Pence on Friday for documents on his possible role in pressuring Ukraine as part of the impeachment investigation of President Donald Trump.

The moved raised the stakes for the White House as Trump fights back to protect his presidency amid allegations he used the powers of his office to enlist Ukraine’s President Volodymyr Zelensky to find dirt on Democratic rival Joe Biden in exchange for military aid.

“Recently, public reports have raised questions about any role you may have played in conveying or reinforcing the president’s stark message to the Ukrainian president,” three Democrats leading the impeachment inquiry wrote in a letter addressed to Pence.

“Pursuant to the House of Representatives’ impeachment inquiry, we are hereby requesting that you produce the documents set forth in the accompanying schedule by 15 October 2019,” they wrote.

They asked for a long list of files, including any documents related to calls between Trump and Zelensky; records of any other meetings and discussions related to Ukraine; and records of Pence’s own communications with Zelensky, Ukraine officials, and Trump administration officials or advisors involved with Ukraine.

Pence’s role in the Ukraine saga remains sketchy. As Trump’s personal lawyer and some US diplomats pressured Kiev earlier this year to help investigate Biden, Pence was first told by Trump to attend Zelensky’s May 20 inauguration.