Axios, citing U.S. officials, reported that the U.S. Army on Tuesday used a B-1 long-range bomber to attack targets belonging to the Islamic Revolutionary Guard Corps in Iran. This was the first mission using this bomber since fighting resumed over the past 12 days.

According to the report, the B-1 bomber carried out its mission after departing from an air base in the UK, and its flight path was seen on online flight-tracking websites.

Axios wrote that B-1 bombers can carry 24 2,000-pound bombs or dozens of cruise missiles, and that the use of this bomber is a sign of a significant escalation and expansion of the U.S. military campaign.

At the same time, Axios, citing informed sources, reported that Qatari mediators are still in contact with U.S., Islamic Republic, and Oman officials in order to reach a new agreement to reopen the Strait of Hormuz and halt the fighting.

A regional source also said that Islamic Republic officials have not yet accepted the latest proposal put forward by the mediators.