In 1971 India and Pakistan were at war with each other once again. At that time, the main naval base of the Pakistani navy was Karachi, which was the main port and commercial center of the country. Consequently, the security of Karachi was an absolute priority for the Pakistanis.
On 23 November 1971, before war was officially declared, due to the tension and clashes that had already taken place, the Indian Navy deployed three Vidyut-class missiles (Soviet Osa I class) which had just entered service. On December 3, the Pakistani air force attacked Indian airfields, prompting India to declare war on Pakistan.
Immediately the Indian Western Naval Command decided to attack the port of Karachi. A task force was formed for this purpose. This included the three missile boats – each carrying four Soviet SS-N-2B Styx surface-to-surface missiles, with a range of over 70 km, two Arnala-class corvettes (of Soviet-origin Petya III class) and a fleet tanker. The commander of the 25th Missile Squadron, Commodore Yadav, was put in charge.
Attacks
On 4 December the Indian squadron sailed within 250 nautical miles (nm) of Karachi and remained there throughout the day to avoid detection. Pakistani strike-bombers could not operate at night and this was what the Indians intended to exploit. Around 10.30pm local time the Indian squadron started sailing towards Karachi.
While sailing the Indians spotted a Pakistani vessel at a distance of 70 nm. about. The Indian missile boat INS Nirghat moved towards the one Pakistani vessel and fired a Styx missile at it. The target was the Pakistani British-built Battle-class destroyer PNS Khaibar. The boat was hit by the missile on its starboard side. An explosion followed in the forward boiler room, as a result of which the vessel could not move.
The Pakistanis, thinking they were attacked by Indian aircraft, started firing indiscriminately against the supposed enemies , even sending a signal that the vessel had been attacked by Indian aircraft and was badly hit. However, the Pakistani vessel incorrectly transmitted its location to the Pakistani naval headquarters, so rescue teams could not find it...
In the meantime the Indian missile, seeing that the Pakistani destroyer had not sunk, launched another missile against it. The missile hit the ship in the other boiler room causing another explosion and blowing up the ship. The destroyer sank, taking with it 222 men of its crew.
At the same time the Indian missile boat INS Nipat fired two Styx missiles, one against the cargo ship Venus Challenger and one against the destroyer PNS Shah Jahan – British-built C-class. The Liberian-flagged lorry carrying ammunition on behalf of Pakistan was literally rocked in the air upon being hit and sank 23 NM. south of Karachi. The destroyer was also badly damaged and was later broken up beyond repair.
Also the Indian guided missile cruiser INS Veer hit the Pakistani minelayer PNS Muhafiz – an American built Adjutant class, which sank immediately, without even having time to send a signal, taking 33 of his men with him to the bottom.
In the meantime the missile boat INS Nipat moved towards Karachi and reaching a distance of 26 nm. launched the two Styx missiles it still had against the fuel tanks at Kemari. One missile did not reach the target due to a problem. But the other hit the target and caused a huge fire.
After completing its mission the Indian squadron withdrew unmolested. It was an amazing win. The Pakistanis the next day launched airstrikes against the Indian port of Okha destroying fuel tanks and ammunition depots. The Indians responded three days later (Operation Python) by sinking three more Pakistani ships. The panicked Pakistanis started hitting any ship in front of them hitting their own frigate PNS Zulfiqar.