The US Air Force (USAF) requires around 100 new long range strike-bombers (LRS-B), a top executive observed weeks after the country put a freeze on the development of the jets.

Speaking in Washington, Air Force Secretary Deborah Lee James said: "We’re looking to buy about 100, 80 to 100 but probably closer to the 100 mark."

Northrop Grumman was selected in October to build the LRS-B at a cost of more than $500m per aircraft.

"We’re looking to buy about 100, 80 to 100 but probably closer to the 100 mark."

However, the programme was halted in November after Northrop’s competitors, a consortium of Lockheed Martin and Boeing, complained to the Government Accountability Office (GAO) against the selection.

The heavy-payload stealth aircraft will be capable of carrying thermonuclear weapons. It is expected to be inducted into the USAF in the 2020s.

James said that the air force is operating with aging equipment.

The air force is the smallest it has been since it was established in 1947 but the busiest it has ever been.

For fiscal year 2017, the Department of Defense is budgeted for $17bn less than requested, she added.

In November, the Mitchell Institute for Aerospace Studies said that 100 LRS-B is a minimal starting point to meet future national security requirements.

The institute’s report, US Bomber Force: Sized to Sustain An Asymmetric Advantage for America, estimates the acquisition requirement to be between 150 and 200 combat coded aircraft.