Democrat Hillary Clinton won the Illinois primary on Tuesday, US networks projected -- her fourth win of the night, after victories in Florida, Ohio and North Carolina.
The only contest of the day yet to be determined was in Missouri, where Clinton and rival Bernie Sanders were running neck-and-neck.
On the Republican side, Donald Trump scored three wins in Florida, North Carolina and Illinois. Ohio Governor John Kasich won the primary in his home state, and Senator Marco Rubio dropped out of the race. Missouri was also undecided.