Iran’s Revolutionary Guard announced on Wednesday that it had seized two vessels and escorted them into Iranian waters in an escalation near the Strait of Hormuz.

In a statement, the Guard said the ships, “MSC Francesca” and “Epaminodes,” were detained for “sailing without authorization and manipulating navigation systems.”

According to the semi-official Tasnim News Agency, the vessels were accused of operating in the المنطقة without the required permits from Iranian authorities.

Earlier on Wednesday, the UK Maritime Trade Operations agency reported receiving alerts that two vessels near the Strait of Hormuz had come under fire from Iranian Revolutionary Guard units.