Fear and tension gripped Pakistan's biggest city when unknown armed men went about the city forcing shops, restaurants, and petrol pumps to down their shutters.
Television channels reported that in a matter of hours, markets and others facilities were closed down in many areas of Karachi and several other cities of the Sindh province.
The affected cities included Hyderabad, Sukkur and Mirpurkhas.
There were also unofficial reports that protest rallies were being planned for tomorrow in Karachi and other cities of the province against remarks made by the Chief Justice of Pakistan against the Mutthaida Qaumi Movement and its leader, Altaf Hussain.
The Supreme Court of Pakistan today issued a contempt notice to Altaf Hussain for making disparaging remarks against the judiciary while addressing different rallies on telephone from London recently.
The court ordered Hussain to be present in court for the hearing on January 7.
Hussain later in the day while addressing party workers said the case would be dealt by the MQM according to the law and constitution.
The MQM chief and the deputy convener of the party's Rabita Committee Farooq Sattar, who is also a lawmaker, were summoned on Jan 7 for criticising the court's directives regarding delimitation of constituencies of Karachi.
Chief Justice Iftikhar Muhammad Chaudhry during the hearing said he had read the text of a speech by Hussain and found it to be offensive and threatening.
He said the language used in the speech was tantamount to an attempt to obstruct justice.
During his speech today, Hussain said they would file a response in the apex court after consulting legal and constitutional experts.
Hussain said efforts were being made to remove MQM from the country's political scene for the last 35 years.
The MQM which represents the Urdu speaking migrants from India is one of the biggest coalition partners of the ruling PPP in Sindh and in the National Assembly.