WASHINGTON—Sen. Joe Manchin (D., W.Va.) raised alarms about inflation in a letter to Fed Chairman Jerome Powell on Thursday, calling on the central bank to start reversing the emergency support it has provided during the coronavirus pandemic.

“With the recession over and our strong economic recovery well underway, I am increasingly alarmed that the Fed continues to inject record amounts of stimulus into our economy,” he wrote.

Mr. Manchin wrote in the letter that he was concerned the Fed’s easy money policies and additional spending legislation in Congress could exacerbate recent spikes in inflation. The Senate is currently working on both a roughly $1 trillion bipartisan infrastructure bill and a $3.5 trillion bill of Democratic priorities, for which Mr. Manchin’s support will be pivotal.

“I am deeply concerned that the continuing stimulus put forth by the Fed, and proposal for additional fiscal stimulus, will lead to our economy overheating and to unavoidable inflation taxes that hard working Americans cannot afford,” he wrote.

The Fed cut its short-term benchmark interest rate to near zero in March 2020 and has been purchasing $120 billion per month in Treasury and mortgage-backed securities to drive down longer-term rates to provide added stimulus.

A top lieutenant to Mr. Powell, Vice Chairman Richard Clarida, said Wednesday that the central bank could announce plans to reduce those purchases later this year. Mr. Clarida also said that significant fiscal stimulus approved by Congress this year might spur a faster recovery that allows the Fed to begin raising interest rates in early 2023.

Mr. Manchin lauded the Fed’s response to the pandemic last year but warned of overstimulating an economy that doesn’t need “policy responses tailored for an economic depression.” He asked Mr. Powell and the Fed’s rate-setting committee “to immediately reassess our nation’s stance of monetary policy and begin to taper your emergency response immediately.”

A Fed spokeswoman declined to comment.

The U.S. inflation rate reached a 13-year high recently, triggering a debate about whether the country is entering an inflationary period similar to the 1970s. WSJ’s Jon Hilsenrath looks at what consumers can expect next. The Wall Street Journal Interactive Edition

Mr. Manchin’s concerns about inflation could weigh on Democrats’ ambitions to pass a major climate, education, and healthcare package in the coming weeks. One centrist Democrat, Sen. Kyrsten Sinema (D., Ariz.), has already said she is opposed to a bill that costs $3.5 trillion. The party is poised to move ahead with a budget blueprint for the bill in the coming days, and Democrats cannot afford any defections on the bill in the 50-50 Senate.

Congress has passed a raft of coronavirus relief legislation since the beginning of the pandemic, including a Democratic-backed $1.9 trillion bill approved earlier this year.

Mr. Manchin’s letter is also noteworthy because the Senate will consider later this year President Biden’s nominee to chair the central bank. Mr. Powell’s term expires in February 2022. The White House is considering whether to extend a second term to Mr. Powell or whether to tap someone else for the job, including one of his colleagues, Fed governor Lael Brainard.

Ms. Brainard has been a forceful advocate for maintaining the Fed’s easy-money policies. In a speech last week, Ms. Brainard said it wouldn’t be appropriate for the Fed to consider tapering its asset purchases before October. Progressive Democrats, including Sen. Elizabeth Warren (D., Mass.), have indicated in recent weeks that they would prefer she be named to the job instead of Mr. Powell.

Political analysts say Mr. Powell would be likely to win Senate confirmation easily because he could attract significant support from both parties. Four current Republicans voted to confirm Ms. Brainard, a Democrat, to the Fed’s board in 2014. Mr. Powell, who was nominated to his current post by Republican former President Donald Trump, won backing from 34 current Democratic senators during his Senate confirmation in 2018.

Write to Andrew Duehren at andrew.duehren@wsj.com and Nick Timiraos at nick.timiraos@wsj.com