Ships passing through the Strait of Hormuz and the Persian Gulf have reported unusual GPS interference, among other problems, and the US believes Iran is to blame.
The Department of Transportation’s Maritime Administration issued a warning on Wednesday about threats to commercial vessels posed by Iran, saying that ships operating in the region could have a variety of issues, including “spoofed bridge-to-bridge communications from unknown entities falsely claiming to be US or coalition warships.”
At least two incidents were said to involve GPS interference, it said.
“Due to the heightened regional tensions, the potential for miscalculation or misidentification could lead to aggressive actions against vessels belonging to US, allied, and coalition partners operating in the Arabian Gulf, Strait of Hormuz, and Gulf of Oman,” US Central Command, which oversees American military operations in the Middle East, said in an emailed statement.
It added that ships had reported experiencing “GPS interference, bridge-to-bridge communications spoofing, and/or other communications jamming with little to no warning.”
In some cases, a US defense official told CNN, Iranian navy and Islamic Revolutionary Guard Corps vessels have spoofed merchant ships’ automatic identification system to make themselves look like commercial shipping vessels.
The official said Iran had GPS jammers operating on Abu Musa Island, in the Persian Gulf near the Strait of Hormuz, apparently to cause ships and aircraft to inadvertently wander into Iranian waters or airspace, thus justifying a seizure.
Following a string of what the US has characterized as limpet-mine attacks on commercial shipping vessels by Iran, Iranian forces began seizing tankers. After British forces seized an Iranian tanker believed to be in violation of European Union sanctions, the Iranians tried to capture the BP oil tanker British Heritage.
Not long after that incident, Iran said it had seized the UK-flagged oil tanker Stena Impero. While the Royal Navy was able to protect the British Heritage, the Stena Impero sailed unescorted.
In the wake of these incidents, the US has worked to establish a coalition to safeguard commercial shipping in the hotbed region. The British defense ministry has already committed the Royal Navy to this mission.
The US has significant assets in the region, including ships and aircraft that were deployed in recent months to counter Iranian threats, and the British frigate HMS Montrose and destroyer HMS Duncan are already defending ships in the area.
“The US remains committed to working with allies and regional partners to safeguard the freedom of navigation, the free flow of commerce, and the protection of US vessels and personnel in this region,” CENTCOM said.