The Pentagon may have far more troops serving in Iraq, Syria and Afghanistan than it has officially told the American public, due to the way some forces aren’t included in an official count. 

Officially, the Pentagon has set force management levels of 8,448 for Afghanistan, 5,262 for Iraq and 503 for Syria. But there are far more troops in all three places, as not all of those units are required to be counted against the force management levels.

Defense Secretary Jim Mattis has previously acknowledged the discrepancy. On Tuesday, Mattis said that before he adds any of the potentially 3,900 troops the Pentagon seeks to carry out President Donald Trump’s revised strategy for Afghanistan, he would square how many troops are there now. 

“The first thing I have to do is ‘level the bubble,’ and account for everybody that is on the ground there now, the idea being that we’re not going to have different pockets that we are accounting for,” Mattis said. 

As of April, there were more than 7,000 forces on the ground in Iraq and more than 900 in Syria, defense officials have previously said on the condition of anonymity. On Tuesday the Wall Street Journal and NBC reported that the actual number of forces in Afghanistan at present is about 12,000, citing unnamed sources. 

If the totals are correct, it would mean the U.S. has about 20,000 boots on the ground in Iraq, Syria and Afghanistan in total, when it reports to the American public that there’s only about 14,000. 

”It is widely known that there are exemptions to the [force management levels] for units and people turning over, and for units and people who may be in theater for a temporary assignment,” said Navy Capt. Bill Salvin, spokesman for Resolute Support, the NATO mission to train, advise and equip Afghan forces. “Temp assignments are generally less than 120 days. In a dynamic combat theater like Afghanistan, it is not surprising that the number of forces on the ground fluctuates.”

Mattis said he would provide the total number of forces on the ground in Afghanistan once accounted for. In June, the White House provided Mattis the authorization to set troop levels as he saw necessary, but it also capped the total additional number Mattis could send at 3,900. 

“I’ll tell you what the total number is, and there is a number that I am authorized to go up to,” Mattis said Tuesday. 

However on Monday, Trump suggested that the Pentagon would not be that transparent. 

“We will not talk about numbers of troops or our plans for further military activities,” Trump said during his speech at Joint Base Myer-Henderson Hall in Virginia Monday announcing the Afghanistan strategy. “Conditions on the ground, not arbitrary timetables, will guide our strategy from now on. America’s enemies must never know our plans or believe they can wait us out.” 

Watch President Trump's entire Ft. Myer speech to troops on Afghanistan

Watch President Trump's full address to troops at Ft. Myer -- and to the nation -- in which he outlined his policy on Afghanistan.

When asked about whether the news reports on up to 12,000 in Afghanistan were correct, Pentagon spokesman Adam Stump followed the president’s lead. 

“The President was crystal clear in his speech about discussing troop levels. We are not going to discuss numbers,” Stump said. 

Mattis said now that the Pentagon has the way forward, he has directed Chairman of the Joint Chiefs of Staff Gen. Joseph Dunford to provide a plan to execute the president’s strategy.  

“When he brings that to me I’ll determine how many more [forces] we need to send in ― it may or may not be the number that’s bandied about up until now. I’ve got to get the plan in from the chairman.” 

Mattis would not confirm or deny that 3,900 forces would be sent. 

“I‘d rather not say a number and then have to change it later on. Let me look at the plan that the military brings me,” Mattis said. ”We’ve given them the strategic goals. They now have to line up the different things they have to do, assign troops to each one of those efforts. Once I see that, look at the number we have on the ground, reorganize those on the ground to align with new strategy and then [I’ll] bring in whatever gap fillers I need.”