Donald Trump shot off a fiery tweet about a Democratic competitor, but this time, he wasn’t bashing them.

Trump has used his Twitter account to criticize Hillary Clinton on multiple occasions:

But he has also used Twitter to weigh in on the Democratic primary.

Several weeks ago, he told his followers that he agreed with a comment made by Bernie Sanders:

On Tuesday, the Republican frontrunner once again dipped his foot into the Democratic primary pool:

Trump is referring to the delegate system in the Democratic primary, which supporters of Sanders have claimed provides Hillary Clinton an unfair advantage.

MIAMI, FL - MARCH 09: Democratic presidential candidates Senator Bernie Sanders (D-VT) and Democratic presidential candidate Hillary Clinton wave to supporters before the Univision News and Washington Post Democratic Presidential Primary Debate on the Miami Dade Colleges Kendall Campus on March 9, 2016 in Miami, Florida. Voters in Florida will go to the polls March 15th for the state's primary. (Photo by Joe Raedle/Getty Images)
Joe Raedle/Getty Images

Sanders and Clinton will face off in five races during the Blue State primaries on Tuesday, when Pennsylvania, Rhode Island, Delaware, Connecticut, and Maryland head to the polls.

Clinton is currently leading Sanders in all five states as of April 26, according to the Real Clear Politics poll average for each state.