Iranian gunboats unsuccessfully attempted to intercept a US oil tanker in the Strait of Hormuz on Tuesday before a US Navy vessel intervened, reports say.

A U.S.-flagged tanker heading for Bahrain was approached and threatened by Iranian gunboats in the Strait of Hormuz, a British maritime security firm says.

Iranian Shahed-139 drone shot down by F-35 jet over Arabian Sea • In separate incident, six Iranian gunboats approach US-flagged oil tanker in Strait of Hormuz

Iran faces rising logistical expenses—from ship-to-ship transfers to tanker reflagging—meaning it pays more just to sell each barrel.

The oil market got another boost from a bullish inventory report from the American Petroleum Institute (API). The numbers show that US crude oil inventories fell by 11.1m barrels over the last week, significantly larger than the roughly 640k barrel draw the market was expecting.

The Treasury Department announced it's sanctioning nine vessels that transport Iranian oil, as well as the ships' owners.

The sanctions announced Friday are in addition to an initial round of penalties issued last week against several senior Iranian officials.

By Scott DiSavino NEW YORK, Feb 3 (Reuters) - Oil prices edged up on Tuesday after the U.S. shot down an Iranian drone approaching a U.S. aircraft carrier and armed boats approached a U.S.-flagged vessel in the Strait of Hormuz,