Israel accused Iran's Revolutionary Guard (IRGC) on Monday of turning commercial ships into platforms for launching missiles, drones and commandos.
Defense Minister Yoav Gallant added the objective was to spread Tehran's clandestine naval clout well beyond the Persian Gulf.
The allegation came as tensions between the regional foes surge afresh over Iran's nuclear drive of uranium enrichment and support for Palestinian and Lebanese militias.
Showing images of six purportedly repurposed Iranian vessels, five of them named, Gallant told the Herzliya Conference security forum that these were "floating terror bases" and that one had recently sailed toward the Gulf of Aden.
"This follows directly on the maritime terrorism Iran has been imposing on the Persian Gulf and Arabian Sea. It is working to expand its activity to the Indian Ocean, too, and later to the Red Sea and to the Mediterranean Sea as well," Gallant said.
Iran has seized dozens of commercial vessels since 2019 in around the Persian Gulf waters, often with the aim of gaining leverage against other countries, such as South Korea and Greece.
Gallant said, “The [Iranian plan] is a concerning, 'pirate policy'. Iran is conducting itself like a collection of criminal organizations and not a modern state. The floating terror bases are an extension of Iran’s ongoing maritime terrorism, as seen in its actions in the Persian Gulf and Arabian Sea."
"Iran aims to expand its reach to the Indian Ocean, the Red Sea and even the shores of the Mediterranean. This is a structured plan designed to threaten trade and flight routes – both military and civilian – and to create a permanent threat in the maritime arena,” he added.