WASHINGTON, April 30 -- US Federal Reserve Chair Jerome Powell, a soft-spoken central banker who chooses his words carefully, is perhaps an unlikely candidate to become one of the few figures who have stood up to President Donald Trump.

Nevertheless, after months of insults, abuse and pressure to lower interest rates, Powell on Wednesday will address what is likely his last press conference as Fed chief - where he is seen by many as having prevailed over the browbeating Republican.

In a statement in January, Powell revealed that Trump's Justice Department had opened an unprecedented investigation into him and the Fed over cost overruns related to building renovations.

At the time, he warned the probe should "be seen in the broader cont...