The United States Navy has shown limpet mine shards as well as a magnet extracted from one of the oil tankers allegedly attacked last week, claiming that they bore striking resemblance to Iranian mines.

According to Cmdr. Sean Kido of the U.S. Navy’s 5th Fleet speaking to reporters at a NAVCENT facility in Fujairah, the UAE, the damage inflicted to the Kokuka Courageous tanker was “not consistent with an external flying object hitting the ship” which contradicted a previous eyewitness testimony earlier revealed by the ship’s owner.

The official added that fingerprints and a hand print have been recovered as a result of the probe conducted by the US Navy.

The already-tense relations between the United States and Iran took a turn to the worse last week following an apparent sabotage attack against two tankers in the Gulf of Oman. The US immediately blamed Iran for the attacks to which official Tehran responded by saying that the US made its claims “without a shred of factual or circumstantial evidence.”

Iranian-US relations have been extremely strained since May 2018, after the US unilaterally withdrew from the 2015 Iran nuclear deal. Exactly one year after the US pullout, Iran announced that it would withdraw from some of its voluntary commitments under the agreement.