Washington says it is doubtful about announcements by Iranian officials that the Islamic Republic is developing a hypersonic missile.

Department of Defense's spokeswoman Sabrina Singh said on Thursday that the US questions the accounts claiming that the Islamic Republic developed a hypersonic missile.

“We've seen the reports asserted and coming out of Iran, we remain skeptical of these reports,” the Pentagon spokeswoman told a news conference.

Commander of Iran’s Revolutionary Guard Aerospace Force, Amir Ali Hajizadeh claimed last week that the regime had built its first missile that can fly at least five times faster than the speed of sound.

“This missile has a high speed and can maneuver in and out of the atmosphere. It will target the enemy’s advanced anti-missile systems and is a big generational leap in the field of missiles,” Tasnim News Agency quoted Hajizadeh as saying.

“We will continue to monitor closely any development or proliferation out of Iran or missile systems,” added Sabrina Sing in reaction to the reports.

IRGC officials and state media have not published any details about their claim and have promised that this missile will be unveiled soon.

Tehran’s claim regarding this weapon comes at a time that tensions between the Islamic Republic and the West over the violent suppression of antigovernment protests, Iran’s nuclear case and its drone supplies to Russia are mounting.

Hypersonic missiles are harder to intercept as they only need a low trajectory in the atmosphere.