May 12 (UPI) — The cost of the United States’ war against Iran has reached $29 billion since it began on Feb. 29, a top Pentagon official told Congress Tuesday.

Acting Defense Department Comptroller Jules Hurst III told the House Armed Services Committee the estimated cost of the U.S.-Israeli military action against the Islamic regime has increased by $4 billion since an earlier estimate he delivered April 29.

The quickly rising costs reflect higher expenditures for equipment repair and replacement, as well as the “general operational costs” of sustaining the operation in the Persian Gulf and Strait of Hormuz, Hurst said during the hearing on the Defense Department’s $1.5 trillion budget request.

The comptroller cautioned that the changing and uncertain nature of President Donald Trump’s conflict with Iran makes cost estimates difficult to pin down.

As of Tuesday, Iran, the United States and Israel were locked in a de facto stalemate over efforts to reopen the vital waterway while a fragile cease-fire was in effect. Trump on Sunday brusquely rejected an Iranian response to a preliminary U.S. peace proposal, casting doubt that the conflict would end anytime soon.

“We have a lot of unknowns there,” Hurst said. “We don’t know what our future posture is going to be. We don’t know how we construct those bases, and we don’t know what part our allies or partners could pay into our MILCON costs.”

Asked by Rep. Pete Aguilar, D-Calif., for a more detailed breakdown, Hurst declined to do so, saying only that “when it’s relevant and required, we’ll share it.”

Hurst appeared alongside Defense Secretary Pete Hegseth and Chairman of the Joint Chiefs of Staff Gen. Dan Caine during back-to-back Pentagon budget hearings in the House and the U.S. Senate on Tuesday.

Their testimony came as widely differing assessments of the true cost of the Iran war were on offer from official and unofficial sources.

After Hegseth first requested $200 billion to fund the war in March, National Economic Council Director Kevin Hassett only days later said the Iran conflict had cost $12 billion over the first six days alone.

CBS News, citing unnamed U.S. officials, reported last month that $50 billion had already been spent on the war, with most of the going toward munitions.

Meanwhile, another analysis has put the cost at $72 billion over the first two months.

Stephen Semler, co-founder of the Security Policy Reform Institute, estimated that’s what it has cost the Pentagon for the war’s operations and weapons as well as U.S. subsidies for Israel’s bombs and interceptors and nearly $12 billion in military assets lost or damaged so far.