Intelligence Suggests Pro-Ukrainian Group Sabotaged Pipelines, U.S. Officials Say

New intelligence reviewed by U.S. officials suggests that a pro-Ukrainian group carried out the attack on the Nord Stream pipelines last year, a step toward determining responsibility for an act of sabotage that has confounded investigators on both sides of the Atlantic for months.

U.S. officials said that they had no evidence President Volodymyr Zelensky of Ukraine or his top lieutenants were involved in the operation, or that the perpetrators were acting at the direction of any Ukrainian government officials.

The brazen attack on the natural gas pipelines, which link...