India's recent successful test of the K-4 submarine-launched ballistic missile (SLBM) from INS Arighaat has elicited sharp reactions from Pakistan's strategic security circles.

Conducted off Visakhapatnam in the Bay of Bengal around 23-24 December 2025, this marks the second trial from the vessel following an initial launch in November 2024.

The K-4, with its 3,500 km range, significantly extends India's sea-based nuclear reach beyond the shorter-range K-15 (750 km), enabling coverage of Pakistan and substantial portions of China.

Zahir Kazmi, Arms Control Adviser at Pakistan's Strategic Plans Division under the National Command Authority, labelled the test a "red flag for global stability". He argued that India's nuclear build-up—encompassing around 150 warheads, fissile material for 138-213 more, Agni-V ICBMs exceeding 7,000 km, and forthcoming Agni-VI—exceeds regional requirements and risks an arms race in the Indian Ocean Region (IOR).

Kazmi highlighted India's planned expansion to six SSBNs and six SSNs by the 2030s, including the 7,000-tonne S4-class like INS Aridhaman, incorporating Russian-derived reactors, Akula-class quieting technology, Thales sonar, and Western commercial off-the-shelf guidance systems.

India's nuclear submarines rely on an 83 MW pressurised water reactor developed by Bhabha Atomic Research Centre (BARC), powering INS Arihant (6,000 tons) and INS Arighaat. INS Arihant, commissioned in 2016, completed India's nuclear triad with land, air, and sea legs, while INS Arighaat joined in August 2024 and can deploy both K-15 and K-4 missiles.

INS Aridhaman, the third Arihant-class SSBN, nears commissioning, potentially by late 2025 or early 2026, as stated by Navy Chief Admiral Dinesh K. Tripathi, enabling three operational SSBNs for continuous at-sea deterrence.

Kazmi perceives a doctrinal shift in India post-Operation Sindoor—the 87-hour conflict in May 2025 targeting terrorist sites in Pakistan and PoK after the Pahalgam attack—as moving from land-air focus to sea-led operations, deploying carrier strike groups with INS Vikramaditya and BrahMos-equipped ships in the Arabian Sea.

He criticised India-US pacts like COMCASA and BECA as eroding the Nuclear Non-Proliferation Treaty (NPT), questioning India's no-first-use (NFU) policy reliability amid alleged "revisionist behaviour" and "drift towards compellence".

Pakistan maintains an estimated 170 stored warheads per SIPRI and has pursued sea-based deterrence via Babur-3 SLCM, first tested in 2017-2018 from submerged platforms using Agosta-class submarines' torpedo tubes, with a 450 km range. Islamabad collaborates with China on Hangor-class submarines—eight in total, four built in China (third launched August 2025 in Wuhan) and four in Pakistan under technology transfer—set for induction from 2026, enhancing A2/AD in the North Arabian Sea. Babur-3 integration on Hangor remains anticipated but unconfirmed officially.

The K-4 test underscores India's maturing second-strike capability under its strict NFU doctrine, bolstering credible minimum deterrence. While Pakistan views this as destabilising, India's Ministry of Defence has issued no official statement, consistent with strategic opacity in SSBN trials.

Amid tense bilateral ties post-May 2025 clashes, both nations' naval nuclear advancements heighten IOR dynamics, with Pakistan renewing its US CIS-MOA in 2023 for equipment access.

This episode reflects broader South Asian strategic competition, where India's triad maturation contrasts Pakistan's focus on tactical and cruise delivery systems. Global observers note the tests' role in validating operational readiness, with multiple trials needed pre-full induction. As INS Aridhaman integrates, India's SSBN fleet will transition towards quasi-continuous patrols, reshaping regional deterrence postures.

Based On The Print Report