US president Donald Trump has said he is quite happy with Steven Mnuchin’s performance despite reports he was dissatisfied with the treasury secretary.

“I am extremely happy and proud of the job being done by @USTreasury Secretary @stevenmnuchin1,” Trump said in a tweet.

The Wall Street Journal reported Trump blames Mnuchin for the appointment of Federal Reserve chairman Jerome Powell, who has been steadily raising US interest rates. Trump is concerned higher rates could undercut economic gains before his 2020 reelection bid, the newspaper reported.

Quoting unnamed sources, it said Trump also expressed displeasure with Mnuchin over stock market turbulence and the treasury secretary’s scepticism about trade actions against China.

“The FAKE NEWS likes to write stories to the contrary, quoting phony sources or jealous people, but they aren*t true. They never like to ask me for a quote b/c it would kill their story,” Trump said on Twitter.

Trump has repeatedly criticised the rate increases under Powell. In October, he called the raises “crazy,” “ridiculous” and “my biggest threat”.

A year ago when Trump picked Powell to head the Federal Reserve, Mnuchin, a former Goldman Sachs banker, was a strong advocate of his nomination to replace Janet Yellen.

Citing a person familiar with the matter, the Journal said Trump, in a conversation with someone who praised Mnuchin’s performance, mentioned stock market volatility and said: “If he’s so good, why is this happening?”

The benchmark Standard & Poor’s 500 index on Friday ended down 10.2% from its 20 September closing high, confirming it had entered a correction, a term used to describe a decline of at least 10% from the previous peak.

When the stock market has posted big gains, Trump has frequently tweeted about Wall Street’s performance. On 2 October, Trump tweeted: “The Stock Market just reached an All-Time High during my Administration for the 102nd Time, a presidential record, by far, for less than two years.”

Mnuchin reportedly tried to moderate Trump’s policy in the trade dispute with China. The Republican president, seeking to slash a $375bn trade gap with China, has imposed tariffs on $250bn of Chinese imports to force concessions.

At a meeting last month, Mnuchin allegedly used the word “we” to refer to the tough-on-China trade practices.

“What do you mean ‘we,’ Steve?” Trump reportedly replied.

Trump has overseen dozens of high-profile departures in his time as president, the latest being Jeff Sessions, the now former attorney general.