The Trump administration is close to bringing forward "major tax reform," Treasury Secretary Steven Mnuchin said Thursday, days after he tempered expectations for how quickly it will pass.

Mnuchin, who this week backed off of his earlier goal of passing tax reform by August, said the White House will unveil a plan "very soon." However, the Trump administration previously missed several of its deadlines for releasing its tax plan.

In terms of timing, he said he hoped passing a tax overhaul will not "take till the end of the year."

Mnuchin spoke at the Institute of International Finance Washington Policy Summit, where White House chief economic advisor Gary Cohn was set to appear later Thursday.

In a Financial Times interview published Monday, Mnuchin said getting a bill to President Donald Trump's desk before August is "highly aggressive to not realistic at this point." He said in February that he wanted to see "very significant" tax reform passed by Congress' August recess.

The business community has hoped Republicans can move quickly on overhauling the American tax system, a prospect that partly fueled stock market gains in the months following Trump's election. However, political realities have tempered expectations for changes to the tax system.

Republicans attempted to pass legislation to replace the Affordable Care Act before moving to a tax reform bill. That effort failed late last month, and Mnuchin said the setback contributed to his assessment that passing a tax overhaul by August could be difficult.

Trump put the pressure back on Tuesday after Mnuchin and Cohn appeared to walk back expectations for how quickly tax reform will happen. He called out Mnuchin by name during a speech at Snap-on headquarters in Wisconsin.

"So we're in very good shape on tax reform. We have the concept of the plan. We're going to be announcing it very soon," Trump said at that time. "But health care, we have to get the health care taken care of, and as soon as health care takes care of we are going to march very quickly. You're going to watch. We're going to surprise you. Right, Steve Mnuchin? Right?"

Even though the president sounded optimistic Tuesday, the Trump administration has set deadlines for tax policy before that have not come to pass. In late February, Trump said the tax plan was "very well finalized," only a day after press secretary Sean Spicer said it would be released "in the next couple weeks.

Republicans have refocused on resurrecting the effort to repeal the ACA, better known as Obamacare, as they get set to return from a recess next week. House GOP leaders are trying to balance the concerns of the both the party's conservative and moderate wings as they try to follow through on a major campaign pledge.

Mnuchin said Thursday that "whether health care gets done or health care doesn't get done, we're going to get tax reform done."

Watch: Tax talk spurs stocks