The U.S. government has contacted South Korean state-run and commercial banks to request that they abide by sanctions against North Korea.

Sources within the South's financial sector said Friday the U.S. Department of Commerce held conference calls with two state-run banks and three commercial banks on September 20th and 21st following the Pyongyang inter-Korean summit.

The Commerce Department is reported to contacted the Korea Development Bank, Industrial Bank of Korea, KB Kookmin Bank, Shinhan Bank and NH NongHyup Bank.

In an unusual move for the U.S. government, officials reportedly asked about the banks' projects involving the North and requested they comply with sanctions.

In fact, during Friday's parliamentary audit, opposition parties expressed serious concerns over the U.S. Commerce Department's move, before urging financial authorities to manage the situation.