U.S. Treasury Undersecretary for Terrorism and Financial Intelligence Stuart Levey has met with Hong Kong financial authorities and executives of major banks to request cooperation in imposing financial sanctions on North Korea for its latest nuclear test and missile launches.

The Associated Press reported Levey held a meeting Thursday with the executives of the world’s biggest bank, HSBC.

A source said on a condition of anonymity that the meeting may have taken place to remind the banks of the possible disadvantages they could face if they do business with North Korea.