[citation needed] The Indian Navy added a squadron to its combatant fleet by acquiring six Osa-class missile boats from the Soviet Union.

The Rajashahi under the command of Lieutenant-Commander Sikandar Hayat managed to evade the Indian blockade and reach Malaysia before the surrender on 16 December.

In the end months of 1971, the Indian Navy's Eastern Naval Command had effectively applied a naval blockade that completely isolated East Pakistan's Bay of Bengal, trapping the Eastern Pakistan Navy and eight foreign merchant ships in their ports.

[citation needed] Instead, a brown water navy was formed consisting a gun boats riverine craft on a permanent basis.

The aircraft successfully attacked many coastal towns in East Pakistan including Chittagong and Cox's Bazar.

[20] The Pakistan Navy responded by deploying her ageing long-range submarine, PNS Ghazi, to counter the threat as the Naval Command had overruled the objections by her officers.

[21] The Indian Navy's Naval Intelligence laid a trap to sink the submarine by giving fake reports about the aircraft carrier.

[22] The deadly game ended when the submarine sank mysteriously while laying a mine with all 92 hands on board around midnight on 3 December 1971 off the Visakhapatnam coast.

[23][24] The sinking of Ghazi turned out to be a major blow and setback for Pakistani naval operations in East Pakistan.

By 3 December prior to starting of the war, the doubts about the fate of submarine had already begun to agitate the commanders at the Naval Headquarter (NHQ).

[citation needed] On 5/6 December 1971, naval air operations were carried out Chittagong, Khulna, and Mangla harbours, and at ships in the Pussur river.

The oil installations were destroyed at Chittagong, and the Greek merchant ship Thetic Charlie was sunk at the outer anchorage.

The Indian Navy therefore decided to carry out an amphibious landing at Cox's Bazar with the aim cutting off the line of retreat for Pakistan Army troops.

On 2 and 3 December, Hangor had detected a large formation of ships from Indian Navy's Western fleet which included cruiser INS Mysore.

Hangor had passed an intelligence to Pakistan naval forces of a possible attack by the observed Indian Armada near Karachi.

On 4 December, the Indian Navy, equipped with P-15 Termit anti-ship missiles, launched Operation Trident against the port of Karachi.

The defence of Karachi harbour was therefore paramount to the Pakistani High Command and it was heavily defended against any airstrikes or naval strikes.

Karachi received some of the best defences Pakistan had to offer as well as cover from strike aircraft based at two airfields in the area.

The Indian missile vessels, of the 25th missile boat squadron, successfully sunk the minesweeper PNS Muhafiz,[7][10][33][34] the destroyer PNS Khaibar[7][10][33][34][35] and the MV Venus Challenger[33][36][37] which, according to Indian sources, was carrying ammunition for Pakistan from the United States forces in Saigon.

[7][33][34][35][36] The missile ships also bombed the Kemari oil storage tanks of the port which were burnt and destroyed causing massive loss to the Karachi Harbour.

[7] Operation Trident was an enormous success with no physical damage to any of the ships in the Indian task group, which returned safely to their garrison.

[12][13] On 6 December, a false alarm by a Pakistani Fokker aircraft carrying naval observers caused a friendly fire confrontation between Pakistan's Navy and Air Force.

A PAF jet mistakenly strafed the frigate PNS Zulfikar, breaking off shortly after the ship got itself recognised by frantic efforts.

During the raid, the Panamanian vessel Gulf Star and the British ship SS Harmattan were sunk and Pakistan Navy's Fleet Tanker PNS Dacca received heavy damage.

[44][45] After the successful operations by Indian Navy, India controlled the Persian Gulf and Pakistani oil route.

Within a few days after the attacks on Karachi, the Eastern fleet of Indian Navy had success over the Pakistani forces in East Pakistan.

"[50] The TT Pistol is still placed in a covered glass display at the Indian Military Academy's Museum.

[49] The damage inflicted on the Pakistani Navy stood at 7 gunboats, 1 minesweeper, 1 submarine, 2 destroyers, 3 patrol craft belonging to the coast guard, 18 cargo, supply and communication vessels, and large scale damage inflicted on the naval base and docks in the coastal town of Karachi.

In actuality, the law and order situation deteriorated with time, particularly after September of the same year when the population turned increasingly against the [Pakistan] Armed Forces as well as the [Yahya's military] government.