Though the MQM held a news conference to denounce the claim and alleged that an ongoing clean up operation in the city was politically motivated, the Rangers said in a press release that the party needs to answer why the weapons were found in its office.
"The presence of such a heavy cache of arms shows there is an existence of anti-state elements in the ranks of political parties," a Rangers spokesman said in the release.
MQM leader Sagheer Ahmed alleged the Rangers had ransacked the office and arrested at least 15 party workers.
"The allegations about the recovery of arms is nonsense and this is a targeted operation against us. During the raid, the Rangers used abusive language against our chief Altaf Hussain and tore down his portrait," he said.
Also Read
The MQM, which is the main political party in Pakistan's biggest city, had made similar claims when one of its former legislators was arrested for the murder of two policemen. The leader was later released by court for lack of evidence.
"The arrested man, Kazim Abbas, belongs to a MQM unit office and we have arrested three other persons with him. They have initially confessed to eight other targeted killings," Hayat said.