US equity indexes traded mixed after a plunge in UnitedHealth Group's (UNH) shares helped push the Dow Jones Industrial Average lower, and as President Donald Trump's call for the termination of Federal Reserve Chair Jerome Powell undermined risk sentiment.

The Nasdaq fell 0.3% to 16,256.1 after midday on Thursday. The S&P 500 rose 0.2% to 5,284.2, clawing back declines from earlier in the session. The Dow Jones Industrial Average dropped 1.6% to 39,030.4 in the holiday-shortened week, with the Good Friday holiday falling on Friday.

All sectors except health care, technology, and communications services rose intraday. Energy, consumer staples, and real estate led the gainers.

In a social media post on Thursday, Trump said Powell should "certainly" lower interest rates. "Powell's termination cannot come fast enough," Trump said, calling the central bank chief "too late."

The president's remarks come a day after Powell reiterated that the impact of US tariffs on inflation may not quickly unwind. "We may find ourselves in the challenging scenario in which our dual-mandate goals are in tension," Powell said, referring to the Fed's goals of gaining maximum employment and stable prices.

Trump said in a separate social media post on Wednesday that "big progress" was made in tariff talks with Japan without mentioning details of the discussions, according to reports from several media publications.

"Of course, the negotiations will not be easy going forward, but President Trump has stated that he wants to give top priority to the talks with Japan," Japan's Prime Minister Shigeru Ishiba said on Wednesday, according to a report from Reuters.

US Treasury yields traded mixed, with the 10-year up 3.6 basis points to 4.32% and the two-year rate 1.5 basis points down at 3.77%.

In company news, UnitedHealth Group's (UNH) shares sank 21% intraday, the worst performer on the S&P 500 and the Dow, as Q1 results fell short of analysts' estimates and the health insurance giant slashed its full-year earnings outlook.

West Texas Intermediate crude oil futures jumped 2.9% to $64.31 a barrel.