Government pension is a global income?

Good afternoon,

I receive a military pension monthly from my country, South Korea. Should I include it as the global income when I report the tax in the U.S.? Last year I asked this question to accounts in South Korea. They told me that I am not required to report it as the global income to IRS because there is an agreement between South Korea and the U.S. government that it is not required to report the pension that is provided by the government to each side. 

Thank you so much!