Sen. Joe Manchin (D-W.Va.) is sending a warning shot to President Biden and congressional leaders, saying he has "serious concerns" about spending $3.5 trillion on a massive package that Democrats want to pass later this year.

Manchin said in a statement early Wednesday that he has "serious concerns about the grave consequences ... if Congress decides to spend another $3.5 trillion."

“Given the current state of the economic recovery, it is simply irresponsible to continue spending at levels more suited to respond to a Great Depression or Great Recession — not an economy that is on the verge of overheating," Manchin said.

He added that "irresponsible levels of spending" could negatively impact the United States' ability to react to "unforeseen consequences."

"I urge my colleagues to seriously consider this reality as this budget process unfolds in the coming weeks and months," Manchin said.

Manchin has previously raised concerns about the debt and Republicans are warning that the spending plan, combined with the $1.9 trillion coronavirus bill, is driving concerns about inflation, which they've used to hammer Democrats in recent weeks.

But his new statement comes only hours after Senate Democrats approved a budget blueprint that includes the $3.5 trillion top line and broad instructions for drafting the spending plan Democrats want to pass this fall without GOP votes.

Senate Majority Leader Charles Schumer (D-N.Y.) touted the adoption of the budget, which unlocks Democrats' go-it-alone approach.

"Democrats have labored for months to reach this point, and there are many labors to come. But I can say with absolute certainty that it will be worth doing. The Democratic budget will bring a generational transformation to how our economy works for average Americans," Schumer said early Wednesday morning.

The budget resolution includes few details or directions to lawmakers about what to include in their spending package, but a memo on the plan sent to Democratic offices said that it's expected to include a swath of the party's top priorities, including immigration reform, universal pre-K, expanding Medicare and combating climate change.

But to get the massive package through the Senate to fund all of the Democratic agenda items, Schumer will need total unity from his 50-member caucus.

Manchin's statement on Wednesday is the latest sign of looming headaches.

Sen. Kyrsten Sinema (D-Ariz.) has already signaled that she won't support a $3.5 trillion price tag and will try to shrink the spending package as Democrats draft and negotiate it in the weeks and months ahead.

“I have ... made clear that while I will support beginning this process, I do not support a bill that costs $3.5 trillion — and in the coming months, I will work in good faith to develop this legislation with my colleagues and the administration to strengthen Arizona’s economy and help Arizona’s everyday families get ahead,” Sinema said in a statement late last month.

But any push to go smaller is likely to spark fierce pushback from progressives, whose votes leadership also needs in both the House and Senate to pass the eventual speaking package.

After Sinema's warning, Rep. Alexandria Ocasio-Cortez (D-N.Y.) fired back: “Good luck tanking your own party’s investment on childcare, climate action, and infrastructure."