"Give me a break, @realDonaldTrump," the Massachusetts senator said
. "You're not losing because it's rigged. You're losing because we see through your creepy bullying."
Warren tweeted at Trump several more times on Wednesday morning, at one comparing the real estate mogul to a child.
"Anyone with children knows that whining about imaginary cheating is the last refuge of the sore loser, @realDonaldTrump," she said
"It's not rigged, @realDonaldTrump," Warren added in another tweet. "You're losing fair & square. Put on your big-boy pants because this is what accountability looks like."
The Trump campaign did not immediately respond to a request for comment on Warren's latest salvo.
Warren has drawn the ire of Trump with her fiery criticisms both on Twitter and the campaign trail. Trump has responded in kind, repeatedly referring to Warren as "goofy" and "Pocahontas" -- the latter a reference to the controversy surrounding the senator's claims of Native American roots.
Warren's Wednesday tweetstorm came hours before the third and final presidential debate, and a day after President Barack Obama also chided Trump over his rigged election claims.
"You start whining before the game's even over?" Obama said during a news conference. "If whenever things are going badly for you, and you lose, you start blaming somebody else then you don't have what it takes to be in this job."
As his poll numbers have cratered in recent weeks, Trump has claimed that the election is being corrupted by voter fraud and a coordinated media campaign designed to sink his campaign. The candidate has urged supporters to monitor polling sites on Election Day.
Many Republicans have repudiated those claims, but Warren said Wednesday that Trump "didn't come up with the 'rigged' election himself."
"It's a longtime effort by the @GOP to delegitimize @TheDemocrats," she said.