Washington (CNN) President Donald Trump repeated a misleading claim about Iran's military budget Saturday, saying it had increased by more than 40 percent since the negotiation of the Iran nuclear deal.

"Iran's Military Budget is up more than 40% since the Obama negotiated Nuclear Deal was reached...just another indicator that it was all a big lie. But not anymore!," Trump tweeted.

Iran's Military Budget is up more than 40% since the Obama negotiated Nuclear Deal was reached...just another indicator that it was all a big lie. But not anymore!

The President made the same claim in announcing his decision to pull the United States out of the Iran nuclear agreement earlier this week -- an assertion that fact checkers have called "exaggerated" and lacking crucial context.

"In the years since the deal was reached, Iran's military budget has grown by almost 40 percent, while its economy is doing very badly," Trump said during the speech.

In a fact check of that remark, The New York Times deemed the claim "exaggerated." Citing data from the Stockholm International Peace Research Institute, the newspaper explained that Iranian military spending has increased by only about 30 percent from 2015, the year the Iran deal was reached, to last year.

The Washington Post also relied on data from the institute in looking into the President's claim and likewise reported an increase in Iranian military expenditures of "nearly 30 percent" from 2015 to last year.

The Post's analysis notes that "just looking at the raw increase or decrease in any country's military budget misses important context." Iranian military spending "increased alongside overall government spending — not in a silo on its own," the newspaper goes on to say, adding that "the nuclear accord has contributed to the overall increase in spending -- including the increase in military spending -- since it lifted sanctions and allowed for a rise in oil production and exports."

The Syrian civil war would have given Iran another reason to boost military spending after the nuclear deal was agreed to in 2015. The conflict, which began in 2011 , was gathering force by 2015, with ISIS claiming territory and gaining strength in its quest to unseat the Assad government.

For Tehran, defending the Syrian regime was non-negotiable, as it ensured Iran's access to Lebanon, helping it project power in the region. There was also an existential element: Syria, under President Bashar al-Assad's father, had taken Iran's side in the Iran-Iraq War, which by some estimates left more than a million dead. For both reasons, the Iranians would have felt they had to come to Syria's aid and start pouring military resources into the fight.