US President Donald Trump on Friday signed an executive order authorizing the secretaries of Homeland Security and Defense to call up military and Coast Guard reservists to active duty, the White House said. The order allows the two secretaries to call up reservists from the Army, Navy, Air Force, and Coast Guard for active duty for up to two years. However, it limits the number to "1,000,000 members on active duty at any one time." "This will allow to us mobilize medical disaster and emergency response personnel to help wage our battle against the virus by activating thousands of experienced service members including retirees," Trump told reporters Friday. "We have a lot of people, retirees. Great, great military people. They're coming back in, who have offered to support the nation in this extraordinary time of need. "And they come back in. They don't say, 'How much?' They don't say, 'What are we getting paid?' They just want to come back in. It's really an incredible thing to see. It's beautiful," he added. Pentagon spokesperson Jonathan Hoffman, who said: "Decisions about which individuals may be activated are still being reviewed. Generally, these members will be persons in Headquarters units and persons with high demand medical capabilities whose call-up would not adversely affect their civilian communities." He added that the departments would consult with state officials before using any National Guard Reserve Component units under the executive order. An Army spokesperson said 14,600 people have expressed interest in joining the national efforts.