Presumptive Democratic nominee Hillary Clinton asked her GOP rival Donald Trump to delete his account after he tweeted his reaction to President Barack Obama’s endorsement of Clinton. The Democratic candidate’s tweet became the most retweeted post of her campaign.

“Obama just endorsed Crooked Hillary. He wants four more years of Obama—but nobody else does!” Trump tweeted after learning about Obama’s support for Clinton. He added, “Crooked Hillary Clinton will be a disaster on jobs, the economy, trade, healthcare, the military, guns and just about all else. Obama plus!”

In reply, Clinton simply tweeted “Delete your account.” Her tweet was liked and shared by more than 400,000 users, which made it the most popular tweet of her campaign.

Trump’s response to Clinton’s tweet was also prompt. “How long did it take your staff of 823 people to think that up–and where are your 33,000 emails that you deleted?” he responded.

One Twitter user wrote “Why would @realDonald Trump do that? He has 2 million more followers than U do. Yea what Priebus said: U R a pro at deleting.” And another advised both the politicians to get off Twitter. “You both should delete your account cuz you both suck either way,” the tweet said.

Obama on Thursday announced his endorsement after a long meeting with Clinton rival and Vermont Senator Bernie Sanders.

“Look, I know how hard this job can be, that’s why I know Hillary will be so good at it. In fact I don’t think there’s ever been someone so qualified to hold this office. She’s got the courage, the compassion and the heart to get the job done,” the Telegraph quoted him as saying. “I have seen her judgement, I have seen her toughness, I’ve seen her commitment to our values up close. I’m with her, and I cannot wait to get out there and campaign for Hillary.”

According to a report by Vox, unlike Clinton, Trump’s tweets are “the purest form of his own self, loud and mocking.”