Officials in Cairo have struggled to control the damage caused by a US intelligence agency which revealed a plan to hide North Korean military shipments bought by Cairo in defiance of international sanctions, Egyptian government documents show.

Recent records obtained include what appears to be an explicit recognition of the Egyptian military’s role in buying 30,000 rocket bombs, which were found to have been hidden on a North Korean cargo ship in 2016, and was heading to an Egyptian port in the Suez Canal at the time of the raid. The UN report described it as the largest seizure of ammunition in the history of sanctions against the communist state (North Korea).

On its part, North Korean officials continued to demand payment for the shipment of arms estimated at $23 million, raising fears of extortion, according to state department documents obtained by the Washington Post, while an Egyptian government spokesman declined to comment on the documents.

The Washington Post published for first time documents on the Egyptian secret deal to buy North Korean bombs in October 2017. The North Korean-owned cargo ship Jie Shun was seized after the CIA alerted Cairo that smuggled material may be on board.

Egyptian authorities uncovered grenades and confiscated the ship. Only then did US officials discover that the beneficiaries of the shipment were the Egyptians themselves. Egyptian officials have never publicly acknowledged the purchase of North Korean military equipment, a practice banned under US and UN sanctions.

The Trump administration officials ordered a freeze in 2017 on the delivery of $300 million in military aid to Egypt, partly because of unspecified secret arms deals between Cairo and Pyongyang. But strained relations with Washington were only part of the fallout from the arms deal, and the new documents appear to show deep concern among Egyptian officials about a range of problems arising from the discovery of the arms shipment, including the possibility of North Korea threatening to expose details of trade ties.

Documents including a memorandum dated May 28, issued by the Egyptian Foreign Ministry between March and May 2017 before Cairo’s role in the transfer of weapons was publicly disclosed and prepared for Egyptian Foreign Minister Sameh Shoukry, discussed resentment of North Korea’s (seizure) or grab of grenades, and made proposals on how to keep the issue calm.

The document referred to a letter North Korea sent to the Arab Organisation for Industrialisation (a governmental organisation) to demand payment.

“The letter again included threats by the North Korean side to reveal their information about the details of this shipment,” the memo said.

The document says the Egyptian company denies knowing about the arms deal, but after several sentences urges a quick financial settlement to keep the North Koreans calm.

“We have made it clear that the state department prefers to expedite the processing of this settlement as soon as possible,” the memorandum said, preferably before Egypt’s rotating membership in the UN Security Council expired in December of that year.

The first public disclosure of the arms seizure occurred in a report issued by the UN Committee of Experts, a monitoring group set up by the council to investigate violations of UN sanctions against North Korea.

The May 28 memorandum outlines a strategy for resolving the payment dispute. Under the plan the Egyptian military intelligence agency planned to undertake negotiations and work through the North Korean military attaché in Cairo.

The memo referred to a recent Egyptian loan to North Korea – details of which were not disclosed in the documents – and noted that Pyongyang may agree to pay a smaller amount for grenades in return for more generous terms of repayment.

“The use of the loan card has already succeeded in pushing the Korean side to communicate with the Egyptian side,” the memo says.

However, how it was eventually resolved – including the amount ultimately paid, if any – was not clear in the documents.

The 2016 incident highlighted an incomprehensible global trade in conventional weapons, which has helped North Korea survive economically, despite tough sanctions imposed by the United Nations and the United States in retaliation for nuclear and ballistic missile tests capable of carrying nuclear weapons.

After being barred from selling coal and other primary products, North Korea resorted to selling military equipment and weapons at discounted prices.

North Korea clients included pariah states such as Syria, as well as sub-Saharan African countries such as Uganda and the Congo, which for decades had relied on North Korea to train and equip its armies. North Korea provided weapons to non-state actors such as Hezbollah, according to UN reports and documents. Because sales are prohibited, North Korea often makes its best effort to hide those transactions.

The bombs were shipped to Egypt in 2016 aboard a ship that sailed under a Cambodian flag, although the ship and cargo were North Korean-owned.

Customs officials who inspected the ship in 2016 saw only piles of “yellow lemonite” (iron stones) in a cargo container. But beneath these stones, dozens of boxes full of grenades were hidden.

A statement presented by the Egyptian embassy in Washington to the Washington Post in 2017 did not directly address violations of the alleged sanctions, but pointed to Cairo’s cooperation with UN officials in finding and destroying contraband.

“Egypt will continue to abide by all Security Council resolutions and will always abide by those resolutions restricting military procurement from North Korea,” the statement said.