Tanker traffic through the Strait of Hormuz absorbed at least 12 attacks during the week of September 28-October 5, the highest weekly count logged since the US war with Iran began on February 28, three maritime security sources told Reuters.

The incidents struck oil, LNG and LPG carriers and ranged from drone overflights and VHF radio hailing to direct projectile hits, according to the US Navy-led Joint Maritime Information Center (JMIC).

"These actions continue to demonstrate Iran's intent to assert presence along key transit lanes and maintain pressure on transiting vessels," the JMIC said in a Sunday advisory.

How does that week stack up against prior peaks?

Maritime security analysts recorded 12 incidents between September 28 and October 5 — the most intense seven-day stretch since the conflict opened. The previous comparable peak landed during the week of July 13, when separate IMO data captured eight incidents.

The UN's International Maritime Organization verified nine incidents in the same September 28-October 5 window. IMO tallies typically lag private trackers because the UN body takes longer to verify and officially record incidents, maritime sources said.

What happened to the On Peace?

India's foreign ministry confirmed on Tuesday that 12 crew members sustained injuries after an unknown projectile struck the Panama-flagged oil tanker On Peace while transiting Hormuz. The strike pushed the week's confirmed casualty count above zero and gave the elevated incident total a hard injury figure to anchor it.

Who is conducting the attacks?

The JMIC attributed the harassment pattern to Iran's Revolutionary Guards, which has persisted with low-level pressure tactics against commercial shipping. Recorded activity includes:

• Drone overflights of laden tankers
• VHF radio hailing of bridge teams
• Surveillance operations against transiting vessels
• Direct projectile strikes on hulls

The frequency, more than the lethality, defines the current campaign. The JMIC's data points to sustained harassment at a level above the conflict's earlier months.

How are Gulf exporters responding?

Crude flows from Gulf producers ran above pre-war benchmarks for roughly half of September, shipping data showed Monday. Output from the region's largest producers held above February baselines through most of the month even as transit risk climbed.

Volume and risk have now risen in the same window. The period that delivered the year's peak weekly attack count also delivered the strongest export cadence since the war began. Tonnage has kept flowing despite the elevated incident rate, though logistical constraints and tanker attacks continue to cloud the outlook for sustained higher volumes.

What does this mean for Hormuz liftings?

The September 28-October 5 peak sets a new benchmark for any shipper, charterer or operator now pricing transit risk. Three variables will govern corridor risk through year-end: the rate at which IRGC harassment continues, the cadence of verified strikes on laden tankers, and the gap between private tracker counts and IMO-verified numbers.

The JMIC's Sunday note carries no immediate de-escalation signal. Both private trackers and the IMO show elevated incident counts into early October, leaving Hormuz transit risk — and its associated war-risk premiums — as a live variable for crude, LNG and LPG liftings through the rest of Q4 and into early 2026.