UNITED NATIONS (AP) — The United States says North Korea is illegally smuggling refined petroleum products into the country beyond the quota of 500,000 barrels per year allowed under U.N. sanctions.

U.S. documents sent to the U.N. Security Council committee monitoring sanctions against North Korea and obtained by The Associated Press Thursday cite 89 instances in which North Korean tankers likely delivered refined products "illicitly procured" via ship-to-ship transfers.

The documents said even if each tanker delivered only one-third of its listed capacity the total volume would be above the 500,000 barrel annual quota.

The United States asked the committee to urgently inform all U.N. member states and the general public that North Korea has breached the quota — and to exercise "enhanced vigilance" against its attempts to obtain refined petroleum products.