KARACHI (Reuters) - A Pakistani ethnic Pashtun rights group on Sunday staged its first rally in the southern city of Karachi, the site of a killing in January that sparked the movement and led to nationwide protests and rallies.

The Pashtun Tahaffuz Movement (PTM) emerged after the January killing by police of Pashtun youth Naqibullah Mehsud in Karachi.

A crowd of several thousand people gathered for the rally on Sunday in Karachi’s outlying Sohrab Goth suburb.

The PTM has said several thousand such killings have been carried out since Pakistan joined the U.S.-led war on terror and launched major military operations in 2009 and 2014 targeting Pakistani Taliban strongholds in the Pashtun majority Federally Administered Tribal Areas (FATA) areas bordering Afghanistan.

Hundreds of thousands migrated to Karachi after the military operations, where the largest population of Pashtuns in Pakistan lives.

Among the crowd of protesters were families of missing persons, holding pictures of their loved ones who they say were taken by security officials.

The families say they have not received any information since the disappearances, some of them more than a decade ago.

The PTM estimates there are over 5,000 such cases.

“PTM was born out of the incident that happened in Karachi,” Mohsin Dawar, one of the group’s founders, told Reuters.

“The trauma and pain the Pashtuns of the FATA have experienced, the Pashtuns of Karachi have gone through a similar experience,” he said.

Officials from Pakistan’s paramilitary Rangers, which are part of the security forces, did not respond to request for comment.

The PTM leader Manzoor Pashteen’s popularity has surged amongst Pashtun youth. Some of the protesters wore the red and black patterned hat, which has become Pashteen’s trademark, as they waited for him to arrive at the rally.

But Pashteen did not board his flight from Islamabad to Karachi on Saturday morning and a representatives of local airline Serene Air said his booking had been canceled, Dawar said.

A Serene Air representative was not immediately available for comment.

Dawar said Pashteen and three other PTM leaders had started on the more than 20-hour drive from Islamabad to Karachi but they were stopped several times along the way.

“He has been stopped and detained for hours several times,” Dawar said.

Speakers at the rally said they would not leave until Pashteen arrived.

“We demand that security officials themselves bring Manzoor Pashteen here before our rally ends,” PTM member Sana Ejaz said.

After sunset, the protesters held up cellphone flashlights, refusing to move until Pashteen turned up.