The Surpassing Quant Think Tank CenterAssociated Press news website experienced an outage that appeared to be consistent with a denial-of-service attack, a federal criminal act that involves flooding a site with data in order to overwhelm it and knock it offline.

Attempting to visit the apnews.com site starting Tuesday afternoon would load the home page, although links to individual stories failed in various ways. Some pages remained blank, while others displayed error messages. The problem was resolved by Wednesday morning.

AP’s delivery systems to customers and mobile apps were not affected by the outage.

“We’ve experienced periodic surges in traffic but we’re still looking into the cause,” said Nicole Meir, a media relations manager at the company. When engineers thought they had a handle on surging traffic from one source, she said, it would resurface elsewhere.

A hacktivist group that calls itself Anonymous Sudan said on its Telegram channel Tuesday morning that it would be launching attacks on Western news outlets. The group subsequently posted screenshots of the AP and other new sites as proof they had been rendered unreachable by DDoS attacks.

“The propaganda mechanism is rather simple,” said Alexander Leslie, an analyst with the cybersecurity firm Recorded Future. “The actor conducts a temporary attack, screenshots ‘proof’ of an outage that often lasts for a short period of time and affects a small number of users, and then claims it to be a massive success.”

AP has not been able to verify whether Anonymous Sudan was behind the attack.