The Associated Press advised its journalists on Tuesday to “practice situational awareness” around its bureaus amid sharp backlash over the news organization’s naming Hillary Clinton as the Democratic Party’s presumptive nominee.

The AP call, which came one day before the closely watched California primary and included superdelegates in its calculations, was quickly picked up by other national news organizations, prompting outrage from staunch Sanders supporters.

The backlash was strong enough for the AP’s vice president for global security, Danny Spriggs, to send out a memo noting staffers had received angry phone calls, emails and messages on social media.

“We have not received any specific security threats,” Spriggs wrote in the memo, which was obtained by Poynter. “It is always good to practice situational awareness around AP bureaus and offices.”

AP staffers weren’t the only targets. The New York Times’ Amy Chozick, who reports on Clinton’s campaign, said Tuesday that she had received multiple threatening calls from Sanders supporters:

I won’t be answering calls from unknown numbers today, after third call from Bernie supporters telling me they’d hunt me down in the streets — Amy Chozick (@amychozick) June 7, 2016

In a blog post defending the AP call, executive editor Kathleen Carroll wrote that the process of concluding Clinton had secured enough delegates to earn the nomination was “very straightforward” and based on a survey of superdelegates as well as pledged delegates won in primary contests.

Sanders accused AP of “hounding” superdelegates to learn their votes and said he was “disappointed” by the news organization’s methods.