A United States official in charge of financial sanctions on North Korea says he is tracing slush funds amassed by North Korean leader Kim Jong-un's family.

Treasury Undersecretary for Terrorism and Financial Intelligence David Cohen spoke on Voice of America and made this remark regarding rumors that the late North Korean leader Kim Jong-il hid a large amount of cash in a Switzerland bank.

Cohen said the U.S. is "very actively looking for where that money may be and if it identifies where it is, it will do everything it can to deprive Kim family’s access to those funds.”

He said Washington is "looking for ways to intensify the financial pressure on North Korea, most importantly, to restrict its ability to finance its nuclear and ballistic missile programs." He explained the sanctions following the North's third nuclear test are similar to how North Korean money held at the Banco Delta Asia bank was sanctioned in 2005.

The undersecretary visited South Korea, Japan and China last month and discussed ways to implement sanctions on the North.