The paramilitary personnel besieged the Khursheed Begum Memorial Hall where the press conference of Rabita Committee members including Farooq Sattar was underway.
According to initial reports, the cameras were forced off as Rangers entered the hall where top MQM leaders were addressing the media.
Sources said the Rangers raided the Nine Zero on reports of presence of a suspect.
They said no arrests were made during the Rangers visit.
They left the MQM headquarters after searching the building and parading the streets.
Farooq Sattar and other party leaders tried to contact the Rangers raiding party to ascertain purpose of the visit, but in vain.
Rangers personnel had also raided the MQM headquarters during the month of Ramazan and rounded up key party leaders Kaiful Wara and Qamar Mansoor.
Wara was later released after questioning, however, Mansoor was kept in detention on charges of listening to provocative speeches of MQM chief Altaf Hussaina and inciting unrest.