Major League Baseball is looking into a now-deleted tweet from umpire Rob Drake warning of a civil war if president Donald Trump is impeached.

According to a copy of the tweet obtained by ESPN, Drake tweeted that he planned to buy an assault rifle "because if you impeach MY PRESIDENT this way, YOU WILL HAVE ANOTHER CIVAL WAR!!! #MAGA2020"."

MLB said in a statement to USA TODAY Sports that the league became aware of the tweet Wednesday and is now investigating the matter.

Drake has been an umpire in the majors since 1999 and was assigned to postseason games in 2010, 2012, 2014 and 2015.

The Twitter account was switched to private mode Wednesday night, but USA TODAY Sports reviewed other tweets from the account before the change was made.

Messages included a claim that Barack Obama was not born in the United States and a tweet to Hillary Clinton calling her an "(expletive) liar," demanding the truth about "#benghazzi."