WASHINGTON—The Biden administration is working with pipeline companies to strengthen protections against cyberattacks following the Colonial Pipeline hack and will announce actions in the coming days, the Department of Homeland Security (DHS) said on Tuesday. The Transportation Security Administration (TSA), a unit of the DHS, “is coordinating with companies in the pipeline sector to ensure they are taking all necessary steps to increase their resilience to cyber threats and secure their systems,” the agency said. The TSA is collaborating with another branch of DHS, the Cybersecurity and Infrastructure Security Agency. DHS said it will release more details “in the days ahead” without providing particulars. The Washington Post reported DHS is preparing to issue its first mandatory cybersecurity regulations on pipelines, citing senior officials. In the past, the TSA has provided voluntary guidelines on cybersecurity for pipelines. The TSA would require pipeline companies to report cyber incidents to the federal government, …