WATCH: Trump's threat to sue over La. delegates explained

BATON ROUGE – Republican presidential candidate Donald Trump threatened to file a lawsuit Sunday afternoon over Louisiana's GOP Convention delegation.

“Just to show you how unfair Republican primary politics can be, I won the State of Louisiana and get fewer delegates than Cruz – Lawsuit coming,” Trump tweeted at 4:11 p.m. Sunday.

Just to show you how unfair Republican primary politics can be, I won the State of Louisiana and get less delegates than Cruz-Lawsuit coming — Donald J. Trump (@realDonaldTrump) March 27, 2016

Trump, who won the Louisiana primary on March 5 with 41.4 percent of the vote, won 18 delegates. Cruz, who tallied 37.8 percent of the vote, also won 18 delegates.

Officially, Trump was declared the winner of the Louisiana GOP primary, even though Cruz tied Trump with delegates won. But here's where it gets messy:

Marco Rubio claimed 5 delegates in Louisiana but suspended his campaign almost two weeks later after losing his home state of Florida on March 15.

According to The Wall Street Journal, Rubio’s five delegates are now “free agents” and can vote for any candidate. Louisiana Republicans believe those votes will move behind Cruz.

The WSJ also reports that the state’s five unbound delegates are also more likely to vote for Cruz instead of Trump, according to Louisiana Republicans.

That means Cruz, who officially lost the primary by 10,896 votes, could walk away with 10 more delegates than Trump.