Donald Trump responded to Hillary Clinton's viral Twitter comeback on Thursday afternoon, escalating the online feud between the two presidential candidates.

In his response, sent several hours after Clinton posted "Delete your account," Trump questioned whether the presumptive Democratic nominee had personally written the tweet and jabbed her for the email scandal that has dogged her campaign since last year.

Clinton had posted the popular Twitter meme on Thursday morning, just minutes after Trump had fired off a tweet lambasting President Barack Obama's endorsement of Clinton.

"Obama just endorsed Crooked Hillary. He wants four more years of Obama—but nobody else does!" Trump wrote.

Clinton's dismissive response instantly blew up, quickly garnering the most retweets her account has ever received, even surpassing Trump's infamous taco-bowl tweet.