CAIRO — On an island in the Suez Canal, a towering AK-47 rifle, its muzzle and bayonet pointed skyward, symbolizes one of Egypt’s most enduring alliances. Decades ago, North Korea presented it to Egypt to commemorate the 1973 war against Israel, when North Korean pilots fought and died on the Egyptian side.

But now the statue has come to signify another aspect of Egypt’s ties to North Korea: a furtive trade in illegal weapons that has upset President Abdel Fattah el-Sisi’s otherwise cozy relationship with the United States, set off a painful cut in military aid and drawn unremitting scrutiny from United Nations inspectors.

Egypt has purchased North Korean weapons and allowed North Korean diplomats to use their Cairo embassy as a base for military sales across the region, American and United Nations officials say. Those transactions earned vital hard cash for North Korea, but they violated international sanctions and drew the ire of Egypt’s main military patron, the United States, which cut or suspended $291 million in military aid in August.

Tensions may bubble up again in the coming weeks with the publication of a United Nations report that contains new information about the cargo of a rusty North Korean freighter intercepted off the coast of Egypt in 2016. The ship was carrying 30,000 rocket-propelled grenades worth an estimated $26 million.