Twitter expands content-moderation rules to cover crises like war and disasters.

Twitter said on Thursday that it was adding new policies aimed at combating misinformation about the war in Ukraine and other crises like natural disasters, an expansion of its rules against misleading content.

The company announced the new policy even as it is in the process of being acquired by Elon Musk, the billionaire chief executive of Tesla and SpaceX, who has said he intends to do away with Twitter’s content moderation policies.

Under its new rule, Twitter will downplay tweets that spread misinformation about crises like natural disasters and wars that could spread rapidly across the platform without intervention. The company will prevent users from retweeting misleading crisis content and block it from appearing in prominent areas, like the home timeline and search features.

In some cases, Twitter will add a warning label to crisis misinformation, alerting users to misleading content, the company said. Misleading tweets from political figures, verified accounts and state-sponsored media outlets will be prioritized for labeling, Twitter said.

The crisis misinformation policy is intended to address misinformation about international armed conflicts, including the war in Ukraine, said Yoel Roth, Twitter’s head of safety and site integrity. Ukrainian officials and Russian diplomats have used their official Twitter accounts to share false and misleading information about the war, and their posts have been widely viewed and shared on the platform.

But the policy has been under development since last year, Mr. Roth noted. At the time, misinformation about wildfires in California were spreading rapidly on Twitter and causing disruptions for firefighters. The new rules could be applied after mass shootings, natural disasters and other global conflicts, Mr. Roth said, or any situation that poses “a widespread threat to life, physical safety, health or basic subsistence.”

Twitter relied on the United Nations’ definition of a humanitarian crisis for its policy, and said it would use information from humanitarian groups, conflict monitors and independent news organizations to assess whether a tweet was misleading.

The move to stop promoting tweets without removing them altogether reflects Twitter’s recent approach to content moderation. After years of criticism from Republican leaders who accused Twitter of censorship and Democratic officials who claimed its rules were too lax, the company has shifted away from simply deleting tweets or leaving them up. Instead, Twitter has begun to limit the viral spread of false and misleading content, and added fact-checking labels.

“Content moderation is more than just leaving up or taking down content, and we’ve expanded the range of actions we may take to ensure they’re proportionate to the severity of the potential harm,” Mr. Roth said. “We’ve found that not amplifying or recommending certain content, adding context through labels and, in severe cases, disabling engagement with the tweets, are effective ways to mitigate harm, while still preserving speech and records of critical global events.”

But the policy could be short-lived. Mr. Musk has indicated that if his acquisition of Twitter closes, he would do away with nearly all its content moderation policies. Mr. Musk has suggested that rather than try to limit misinformation, Twitter should moderate only content that violates local laws.