A secret cyberattack against Iran in June wiped out a critical database used by Iran’s paramilitary arm to plot attacks against oil tankers and degraded Tehran’s ability to covertly target shipping traffic in the Persian Gulf, at least temporarily, according to senior American officials.

Iran is still trying to recover information destroyed in the June 20 attack and restart some of the computer systems — including military communications networks — taken offline, the officials said.

Senior officials discussed the results of the strike in part to quell doubts within the Trump administration about whether the benefits of the operation outweighed the cost — lost intelligence and lost access to a critical network used by the Islamic Revolutionary Guards Corps, Iran’s paramilitary forces.