US President Donald Trump said Energy Secretary Rick Perry will step down by the end of the year, Reuters reported.

According to the agency, the US president made this statement the day before the final date set by the Democratic Congress to deliver documents as part of an investigation into impeachment of the president.

At a campaign in Texas, Trump said he knew about Perry's upcoming resignation for several months.

Perry is expected to be replaced by current Under Secretary of Energy Dan Brollett.

Earlier, 69-year-old Perry said he did not plan to leave his post, refuting a media report that in November he was to announce his resignation.

Recently, it turned out that Perry was featured in an investigation into the impeachment of the US president. The US House of Representatives sent him a summons on October 10 requesting documents that showed what role he played in Trump's attempt to force Ukraine to launch an investigation into his political rival Joe Biden.