A U.N. investigation uncovered an arrangement between Egypt and North Korea in which Egyptian business executives ordered millions of dollars worth of rockets from North Korea for their country's military, according to U.N. officials and Western diplomats familiar with the findings, The Washington Post reported .

The business executives planned to keep the transaction hidden, but an investigation was prompted in August after a secret message was sent from Washington, D.C., to Cairo warning of a vessel headed toward the Suez Canal. The ship was flying Cambodian colors but had left from North Korea and was carrying a North Korean crew. Its cargo was hidden by large, heavy tarps.

Once the ship entered Egyptian waters, customs agents boarded and discovered a stockpile of more than 30,000 rocket-propelled grenades worth $23 million concealed underneath bins of iron ore. The U.N. said it was the "largest seizure of ammunition in the history of sanctions against the Democratic People's Republic of Korea," according to The Post.

This incident is the latest in Egypt's sanctions-defying acts and serves as a critical financial lifeline to North Korea, which is facing tough economic sanctions from the U.N. following its testing of nuclear weapons and ballistic missiles.

It is not clear whether North Korea was ever paid the $23 million for the weapons. A statement from the Egyptian Embassy in Washington, D.C., said Egypt will "continue to abide by all Security Council resolutions and will always be in conformity with these resolutions as they restrain military purchases from North Korea according to The Post .