On 19 June 1992, an operation was held in Karachi by the Sindh Police and Pakistan Rangers, with an additional assistance from the Pakistan Army and its related intelligence agencies.

MQM founder and leader Altaf Hussain considers June 19 as a black day in the history of Pakistan.

More than 18,000 workers were killed. Thousands were arrested and brutally tortured.

According to Altaf Hussain, the ‘Operation-cleanup’ commenced against 72 big fishes, to put an end on the rising terrorism, but it targeted MQM specifically.

June 19, 1992, was the day when an atrocious state operation was started against a peace-loving and patriotic party,” stated Altaf Hussain in a press statement.

19th June 1992 operation Blue Fox was started against 72 big fishes was turned toward #MQM & Muhajirs,
We never forget this.@AltafHussain_90#MQMUSA_Convention_2021 #جون19_شب_خون pic.twitter.com/nq6ppLszyL

— Abdul Hafeez (@2642671BlochReg) June 19, 2021

Blackest day in history of humanity. Day began with blood shed of Urdu speakers which converted in flood. #جون19_شب_خون pic.twitter.com/qMo3voJ6Pt

— Nouman Saddique (@NoumanSaddique8) June 19, 2021

19th June 1992 known as the darkest day in history of #Pakistan,when "OperationBlueFox" was launched by military to grab 72 big fishes but instead, it turned to eliminate #MQM & Muhajirs.@AltafHussain_90#MQMUSA_Convention_2021 #جون19_شب_خون pic.twitter.com/z4p9h8BdXb

— Abdul Hafeez (@2642671BlochReg) June 19, 2021

The MQM hold prayers for its deceased workers at the Lal Qila Ground.

The operation was planned by FIA, Intelligence Bureau and launched under the directives of Prime Minister Nawaz Sharif in 1992, the program was more roughly pursued by upcoming Prime Minister Benazir Bhutto in 1993–94, as part of her internal policies.