On Dec. 23, 2023, the Pentagon reported Iran had directly targeted international shipping. "The motor vessel CHEM PLUTO, a Liberia-flagged, Japanese-owned, and Netherlands-operated chemical tanker was struck at approximately 10 a.m. local time today... by a one-way attack drone fired from Iran," a spokesman said. While the Lebanese Hezbollah, the Yemen-based Houthis, and Gaza-based Hamas have previously targeted shipping with drones and missiles, the Iranian leadership traditionally denies responsibility. Tehran's proxy warfare constitutes a core component of its strategy of plausible deniability.