The United States is taking financial action to block Lybia's leader and his family from using $30 billion-worth of assets in the country.

A U.S. Treasury Department official announced the freeze on Monday.

Lybia's Muammar Gaddafi and five children in their 30s are the target of a United Nations asset freeze, which calls for countries, including the United States, to block wealth owned or controlled directly, or indirectly.

Wikileaks recently released a secret State Department cable from January of last year showing that Lybia's investment fund had $32 billion in liquid assets. Several American banks each managing between $300 million to $500 million in funds.

Where that extra $2 billion may have gone is still in question.

The joint asset freeze came into effect over the weekend when countries including China, France, Russia and the United Kingdom joining the U.S. and others. The asset freeze is part of other sanctions. Independently, Switzerland say it froze assets but hasn't said how much.

Any assets frozen under the UN agreement will be held until sometime in the future to benefit the Libyan people. Some exceptions to the freeze include money identified for basics such as food, rent, medicine, taxes and legal services. People linked with the family may also be added to the list later.

While $30 billion may be substantial sum, Mohamed Layas, the Lybaian investment fund chief, told U.S. officials last January that Libya's primary investments were in London, in banking and residential and commercial real estate.

The U.K has also announced its own freeze.