A Japanese daily says the U.S. is reviewing financial sanctions on several Asian banks that manage North Korean assets.

Citing a source within the Obama administration, the Yomiuri Shimbun says the measures are part of unilateral sanctions being imposed on the North by the U.S. for sinking the South Korean warship, "Cheonan."

The U.S. is targeting sanctions on at least three financial institutions, including one Chinese bank.

Yomiuri suspects North Korean deposits at the banks will exceed the 25 million dollars discovered at the Macau-based Banco Delta Asia (BDA). Washington proposed that all U.S. banks and companies sever ties with the bank in 2005 before enforcing sanctions in 2007.

The paper said that if the U.S. places sanctions on multiple banks, it will deal a heavier blow to North Korea than the 2007 BDA sanctions.