Wednesday night, Israeli planes struck a weapons depot outside Damascus, reportedly killing three pro-Iran fighters. While such attacks have become both routine and widely known, the IDF has also been fighting the Islamic Republic at sea, a fact only recently brought to public attention because of an explosion on an Iranian military vessel on Tuesday. Ron Ben Yishai explains:

The vessel that was hit, the Saviz, is actually a floating naval base for the Iranian Revolutionary Guard Corps in the Red Sea, off the coasts of Yemen and Djibouti—whatever Iran says to the contrary. . . . The Saviz was actually in the area to protect Iranian ships in the Red Sea and to grant fast-moving Revolutionary Guard commando boats freedom of movement. . . . These boats are kept onboard the Saviz for use by the commando forces who protect Iranian oil tankers and vessels smuggling weapons as they make their way to Syria and Lebanon through the Suez Canal.

The vessel also acts as an intelligence base, monitoring Saudi vessels that are enforcing a maritime embargo on Iranian-backed Houthi rebels in Yemen and preventing humanitarian aid from reaching them.

The attack marks an escalation in the ongoing covert war being waged at sea between Israel and Iran. Its aim was threefold: to retaliate for an Iranian attack on an Israeli-owned cargo ship in the Arabian Sea last month; to show the Iranians that Israel has the upper hand in the waters of the Red Sea and the Mediterranean, and that Tehran would be wise to . . . end efforts to smuggle oil and arms to Syria and Lebanon; [and] to clarify to the United States that Israel will continue its relentless fight against Iran’s subversive actions in the region, whether it is in Syria, Lebanon, Iraq, or Yemen—even if the U.S. is attempting to rebuild relations with the Islamic Republic.

Israel will likely respond directly against Iran after yesterday’s attack, and has made known that it will calibrate its retaliation based not on the extent of the damage, but on the scale of the attack. The specifics are anyone’s guess, but Edward Luttwak has a suggestion, put forth in an article published just hours before the missile barrage: cut off Tehran’s ability to send money and arms to Shiite Arab militias.

In practice, most of this cash comes from a single source: oil. . . . In other words, the flow of dollars that sustains Israel’s enemies, and which has caused so much trouble to Western interests from the Syrian desert to the Red Sea, emanates almost entirely from the oil loaded onto tankers at the export terminal on Khark Island, a speck of land about 25 kilometers off Iran’s southern coast. Benjamin Netanyahu warned in his recent speech to the UN General Assembly that Israel’s “long arm” can reach them too. Indeed, Khark’s location in the Persian Gulf is relatively close. At 1,516 kilometers from Israel’s main airbase, it’s far closer than the Houthis’ main oil import terminal at Hodeida in Yemen—a place that was destroyed by Israeli jets in July, and attacked again [on Sunday].