A series of “near-miss” encounters between American and Iranian forces in the Persian Gulf is pushing U.S. officials concerned about a broader conflict to weigh establishing a direct military hot line with the Islamic republic.

U.S officials said they are especially worried about a fleet of speedboats likely controlled by the Islamic Revolutionary Guard Corps, Tehran’s elite military force. The high-performance boats, which can be equipped with missiles, regularly challenge U.S. and allied warships that transit through the Persian Gulf.