Iran has received more than $10 billion in sanctions relief from around the world in the form of cash and gold in the past three years, since it signed a preliminary nuclear deal with world powers, The Wall Street Journal has revealed.

The large shipments of gold and cash, from oil funds unfrozen in numerous countries, represent the kind of financial relief that made Iran’s leaders eager to complete the international nuclear accord, officials told the newspaper.

Some of the cash and gold went to Iran while the U.S. and other world powers negotiated with Tehran on a final nuclear deal. More shipments took place after final deal went into effect last January, according to the current and former American officials.

This tallying of the sanctions relief to date includes payments previously announced and others that haven’t been. In one previously unreported payment, the U.S. authorized Iran to receive $1.4 billion in sanctions relief between when the final deal was struck in July 2015 and when it took effect, the U.S. officials told The Wall Street Journal.

Some U.S. lawmakers and Middle East allies have warned that the shipments of cash and gold, a highly liquid form of money, can be used to fund Iran’s allies in the region, including the Assad regime in Syria, the Hezbollah terrorist group in Lebanon and the Houthi rebels in Yemen.

“Forking over cash and gold to the world’s leading state sponsor of terror is incredibly dangerous,” said Rep. Ed Royce (R., Calif.), chairman of the House Foreign Affairs Committee, who sponsored a House-passed bill to ban such payments, told The Wall Street Journal.

A spokesman for the Iranian government did not respond to a request for comment.

The Wall Street Journal noted that world powers began easing sanctions against Iran in January 2014 after the preliminary accord went into effect. Negotiators agreed to allow Iran monthly payments of $700 million, to continue until a final deal was reached. Tehran recouped a total of $11.9 billion between January 2014 and July 2015.

The U.S. authorized Iran to receive another $1.4 billion between when the final deal was reached and when it took effect. One senior administration official described that money, which hasn’t previously been reported, as a bridge to the deal’s full implementation.

The $10 billion of cash and gold was moved through third-party countries in the Middle East and Europe, according to the officials who spoke to The Wall Street Journal. The process began with countries such as Japan, India and South Korea unfreezing Iranian oil revenues held in international bank accounts, then wiring the funds to banks in Oman and United Arab Emirates, and at times to institutions in Switzerland and Turkey, the officials said.

The money then was converted to currency and bars of gold, the officials told the newspaper. The only restriction the White House put on the transactions was that the cash couldn’t include U.S. dollars.

To enable the flow of the $700 million monthly payments, the White House signed a series of legal waivers authorizing countries to unfreeze Iranian oil revenues, the officials revealed. Without the waivers, those countries in many cases would have been in violation of U.S. secondary sanctions.

Other sums were kept in foreign banks, and portions less than $20 million often were wired through small Iranian banks that weren’t sanctioned, or were moved by institutions that handle transfers such as family remittance payments, the officials told The Wall Street Journal.

The officials further said a final deal with Iran might not have been possible if they hadn’t found ways to get Iran some of the monthly $700 million payments during the 18 months of negotiations.

U.S. officials estimate that roughly half of the $100 billion Iran is entitled to receive under the final deal already is committed to debts Iran has had to pay to other countries, including China.

The $10 billion in gold and cash Iran already has received does not include the separate $1.7 billion cash payment the White House helped airlift to Iran early this year.

Washington says the $1.7 billion payment was to settle a decades-old legal dispute over a failed arms deal. That exchange coincided with Iran’s release of four U.S. citizens imprisoned in the country, leading to speculations that the payment was, in fact, a form of “ransom” for the four Americans.

President Barack Obama and other U.S. officials have insisted the payment didn’t amount to ransom and was only liked to the longstanding dispute over the failed arms deal.

Obama administration officials stressed to The Wall Street Journal that, unlike that $1.7 billion, the U.S. wasn’t directly involved in facilitating the transfer of the $10 billion in cash and gold to Iran.

“If they wanted to convert the oil revenues into cash, they had to do it by themselves,” a senior administration official said. “The U.S. played no direct role.”