Sen. Rand Paul, R-Ky., tweeted Monday that the U.S. is involved in so many military conflicts that Sen. Lindsey Graham, R-S.C., "can't keep track anymore."

"You know you are in too many wars in too many places when even warmonger Lindsay Graham can't keep track anymore," Paul tweeted.

Paul's tweet was responding to Graham's comments on Sunday that he was not aware of the scope of U.S. military presence in Niger.

"I didn't know there was 1,000 troops in Niger," Graham said on NBC's "Meet The Press."

Four U.S. soldiers were killed in an ambush in Niger by the Islamic State two weeks ago.

During the interview, Graham said that the Department of Defense would be briefing lawmakers next week "as to why they were there and what they were doing."