Iran’s Revolutionary Guards say that one of three oil tankers had caught fire after an explosion while attempting to pass through what they described as a mined route south of the Strait of Hormuz, and that the two other tankers had turned back, according to Reuters.

The Guards say the Strait of Hormuz was under their control and “completely closed” while US actions continued in the region, warning that no tanker would be allowed to enter or leave without coordination with Iran.

The statement gave no vessel names or timing for the incident.