2 'dark ships' were spotted near the Nord Stream pipeline leaks days before the explosions were detected, satellite data analysis firm says

• Two "dark ships" were spotted near the Nord Stream leaks, a satellite data analysis firm says.
• It detected 25 ships near the leak sites, two of which had turned off their trackers, Wired's Matt Burgess reported.

Two ships with their trackers turned off sailed near the leak sites of the Nord Stream 2 pipelines just days before the pipelines were ripped open by subsea explosions, a satellite data analysis firm says.

The vessels were both between 311 feet and 426 feet long, and had their automatic identification systems, or AIS trackers, switched off, said Jerry Javornicky, the cofounder of SpaceKnow, Wired's Matt Burgess reported.

"They had their beacons off, meaning that there was no information about their movement, and they were trying to keep their location information and general information hidden from the world," Javornicky told the outlet.

Javornicky said SpaceKnow found 25 ships passing through an area with a several-mile radius around the leak sites, Wired reported. Two of those vessels did not have their AIS data turned on, Javornicky said, per Wired.

The International Maritime Organization mandates that ships with cargo of 330 tons or more, as well as passenger ships of any size, have to turn on their AIS trackers on international voyages.

A ship switching off a transponder is often seen as a red flag, and such a practice is common for vessels engaged in illicit activities such as illegal fishing, human trafficking, and dodging sanctions. US authorities call it a deceptive shipping practice, and advise ports to be wary of ships that manipulate their trackers.

Otto Tabuns, the director of the NGO Baltic Security Foundation, told Wired that it's rare for a ship to turn off its AIS transmitter in the Baltic Sea unless the vessel had "clandestine objectives."

Javornicky's claims come as Western European nations continue to investigate the leaks in the Nord Stream pipelines, which make up the largest network supplying natural gas from Russia to Europe.

Several underwater explosions in late September ruptured the Nord Stream pipelines in the Baltic Sea, but it's still unclear what — or who — is responsible for the damage. Russia, Ukraine, the US, and the UK have all been accused of sabotage, though all have denied such allegations.

German officials said shortly after the leaks that they suspected the gas pipelines were sabotaged by Russia, while Denmark and Sweden said in a letter to the UN that they believed "several hundred kilos" of explosives were used to damage the pipes.

All three nations have kept their findings under wraps.