Washington, April 28 : The United States faces an â??unprecedentedâ?? missile threat environment, with senior defence officials warning lawmakers that the countryâ??s current homeland defences are limited and increasingly vulnerable to advanced weapons, including hypersonic and cruise missiles.

Testifying before a Senate panel, Assistant Secretary Marc Berkowitz said rivals are â??expanding, diversifying and increasing the sophistication of their arsenals of missiles and aerial weapons,â?? posing â??truly grave threats to our homeland, to the American population, to our critical infrastructures, and to our second strike capability.â??

He acknowledged that the existing system offers only â??very limited capabilityâ?? beyond defending against a small-scale intercontinental ballistic missile attack and that the US currently has â??no defence against hypersonic weapons or cruise missiles.â??

General Michael Guetlein described the programme as â??a layered, integrated shield designed to defend the homeland against the full spectrum of advanced threats.â??

â??Our nationâ??s margin of safety has vanished,â?? Guetlein said, adding that â??the homeland is exposed and relatively undefendedâ?? against a new generation of threats that are â??unprecedented in their speed, numbers and lethality.â??

The proposed system would integrate sensors and interceptors across land, sea, air and space, combining kinetic and non-kinetic responses. Officials said it would also leverage artificial intelligence and next-generation processing to improve targeting and response times.

Guetlein said the goal is to deliver an operational capability by 2028, supported by a funding request that includes more than $17 billion in the near term. The full projected cost of the programme is estimated at about $185 billion through the 2030s.

Lawmakers raised concerns over both the cost and the funding mechanism. Senator Angus King questioned the use of a reconciliation process outside the traditional appropriations route, calling it â??a huge mistakeâ?? and warning it reduces congressional oversight.

King also pressed officials on whether the longstanding doctrine of nuclear deterrence remains sufficient. Berkowitz responded that the current strategic environment is more complex than during the Cold War, noting the presence of â??multiple nuclear armed rivalsâ?? with advanced missile capabilities.

He argued that missile defence would complement deterrence, providing â??both a sword and a shieldâ?? to strengthen security and protect civilians if deterrence fails.

Officials described Guam as â??an undisputable part of the homelandâ?? and a key hub in the Indo-Pacific. Lieutenant General Frank Lozano said the Guam defence system is progressing on schedule, with a projected cost of about $3.5 billion.

Military officials emphasised lessons from recent conflicts in Ukraine and the Middle East, pointing to the growing complexity and volume of missile threats. Lieutenant General Heath Collins said the US has issued â??hundreds of updatesâ?? to defence systems in response to real-time battlefield data.

They also acknowledged challenges in scaling production and maintaining interceptor inventories, warning that sustained investment will be needed to meet future demand.

/IANS