TEHRAN — Iran’s foreign minister on Tuesday defended a nuclear deal provision that allows Tehran to begin ramping up its nuclear program after 10 years, a day after the secret document was revealed, leading to concerns over the effectiveness of the landmark nuclear deal.

Mohammad Javad Zarif said the document, submitted by Iran to the International Atomic Energy Agency and outlining plans to expand Iran’s uranium enrichment program, was a “matter of pride.”

He said it was created by Iran’s “negotiators and experts.”

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Zarif’s remarks, carried by the semi-official Fars news agency on Tuesday, followed revelations the day before of the confidential document — an add-on agreement to the nuclear deal signed last year with world powers — that Iran gave the IAEA.

The document, obtained by The Associated Press in Vienna, outlines Tehran’s plans to expand its uranium enrichment program after the first 10 years of the nuclear deal, essentially allowing it to get within six months or less of building a nuclear weapon well before the deal’s 15-year expiration date.

The document is the only part linked to last year’s deal between Iran and six foreign powers that hasn’t been made public. It was given to the AP by a diplomat whose work has focused on Iran’s nuclear program for more than a decade, and its authenticity was confirmed by another diplomat who possesses the same document.

In response, a senior Israeli official told The Times of Israel that Jerusalem’s greatest concern about the nuclear deal with Iran “was and remains that after about 10 years, it would leave Iran with an industrial uranium enrichment capacity that would enable the regime to produce the fuel for many nuclear bombs in a very short time.”

The nuclear agreement “removes the restrictions on Iran’s nuclear program based on dates certain, rather than on changes in Iran’s aggressive behavior, including its support for terrorism around the world,” the senior official said. “The deal doesn’t solve the Iranian nuclear problem, but rather delays and intensifies it.”

Centrifuges churn out uranium to levels that can range from suitability as reactor fuel and for medical and research purposes to much higher levels, for the core of a nuclear warhead. From year 11 to 13, says the document, Iran can install centrifuges up to five times as efficient as the 5,060 machines it is now restricted to using.

Those new models will be fewer in number than those being used now, ranging between 2,500 and 3,500, depending on their efficiency, according to the document. But because they are more effective, they will allow Iran to enrich at more than twice the rate it is doing now.

The US says the Iran nuclear agreement is tailored to ensure that Iran would need at least 12 months to “break out” and make enough weapons-grade uranium for at least one weapon.

But based on a comparison of outputs between the old and newer machines, if the enrichment rate doubles, that breakout time would be reduced to six months, or even less if the efficiency is more than double, a possibility the document allows for.

The document also allowed Iran to greatly expand its work with centrifuges that are even more advanced, including large-scale testing in preparation for the deal’s expiry 15 years after its implementation on January 18, 2016.

Iran has insisted it is not interested in nuclear weapons, and the pact is being closely monitored by the International Atomic Energy Agency. The IAEA said Tehran has essentially kept to its commitments since the agreement was implemented, a little more than six months after Iran and the six powers finalized it on July 14, 2015.

Speaking a few days ago on the anniversary of the deal, US President Barack Obama and Secretary of State John Kerry praised the deal.

“As of today, one year later, a program that so many people said will not work, a program that people said is absolutely doomed to see cheating and be broken and will make the world more dangerous, has, in fact, made the world safer, lived up to its expectations, and thus far produced an ability to be able to create a peaceful nuclear program with Iran living up to its part of this bargain and obligation,” said Kerry, one of the main architects of the accord.

“The Iran deal has succeeded in rolling back Iran’s nuclear program, avoiding further conflict and making us safer,” Obama said in a statement released by the White House on Thursday.