India successfully test-fired the K-4 submarine-launched ballistic missile (SLBM) from the nuclear-powered submarine INS Arighaat in the Bay of Bengal. The missile, developed by DRDO, has a range of approximately 3,500 km and can carry a nuclear warhead. This test, reportedly the second from INS Arighaat, signifies a major step towards the K-4's operational readiness and enhances India's sea-based nuclear deterrence and second-strike capability, placing it among nations with advanced underwater launch capabilities.