Strengthening his virtual lock on the Democratic nod for president, Joe Biden on Tuesday swept party primaries in a trio of key states from east to west: Florida, Illinois, and Arizona.

Former Vice President Biden was already leading the Democratic presidential race after securing strong victories against Senator Bernie Sanders on Super Tuesday and last week’s primaries.

“Today, it looks like once again, in Florida and Illinois — we’re still waiting to hear from Arizona — our campaign has had a very good night,” Biden said in a livestreamed speech on Tuesday.

Sanders is not mathematically out of the race yet,

Read more: US: Biden sweeps primaries in states of FL, AZ, IL