ISLAMABAD (Reuters) - A Pakistani leftist youth organization said on Tuesday that nine of its members went missing in Karachi after demonstrating in support of an ethnic rights movement that has worried the country's security establishment. An organizer for the Progressive Youth Alliance said seven members were abducted after staging a pro-Pashtun Tahaffuz Movement (PTM) rally in Karachi on Sunday, and another four were picked up on Tuesday after another demonstration, also in Karachi. Two of the men picked up on Tuesday have now been released, Anam Khan, organizer of the women's wing of the socialist group, told Reuters. The PTM emerged after the killing by police of Pashtun youth Naqibullah Mehsud in Karachi in January triggered nationwide condemnation and demonstrations attracting thousands. The PTM has since staged a number of protests criticizing the powerful military and its actions in majority ethnic Pashtun areas bordering Afghanistan, often attracting swarms of supporters in Pakistan's larger cities. The PTM's most recent rally on Sunday in the central city of Lahore attracted over 8,000 people despite pressure by security officials to call it off and the mysterious appearance of sewage water onto the protest grounds. Khan said four of the seven men taken on Sunday had boarded a train leaving Karachi when security officials belonging to the paramilitary Rangers arrived and identified them using videos from the protest. Rangers officials did not respond to a request for comment and Karachi police said they were not aware of the incident. On Tuesday the Youth Alliance staged a protest asking for their missing members to be released. "During our protest some men in plainclothes showed up and told us to shut it down," Khan said. "When we were walking away, four of our comrades ... were put in a car." Another activist from the organization also said the abductions had taken place. A witness from a rights advocacy group who was present at Tuesday's protest confirmed seeing the four men being abducted. While not naming PTM, Pakistan's army chief Qamar Javed Bajwa said at an April 12 meeting with dignitaries that "no anti-state agenda in the garb of engineered protests" will be allowed to succeed. A number of prominent Pakistani columnists have complained on Twitter that their articles on PTM were rejected by local newspapers without explanation.