Islamabad, March 11 (IANS): A heavy contingent of paramilitary Pakistan Rangers raided the headquarters of the Muttahida Qaumi Movement (MQM) in Karachi on Wednesday morning, prompting protests by party activists and a call for a day of "peaceful mourning", a media report said Wednesday.

According to sources, a number of party workers, including the party's Rabita Committee, central coordination cell of the MQM, member Amir Khan were detained during the raid, Dawn online reported.

Rangers personnel after breaking the barricades leading to MQM headquarters cordoned off the area and searched through departments of the party's offices and raided adjoining houses and arrested a number of activists and leaders.

According to Rangers spokerperson, Colonel Tahir, ammunition stolen from Nato containers was also seized during the search operation.

MQM senior leader Haider Abbas Rizvi confirmed the raid and said that all the weapons seized by Rangers were licensed.

Soon after the news of the search operation broke out, MQM leaders and activists started to gather outside the headquarters but they were not allowed to enter its premises.