Fears for Western hostages being held by the Taliban arose on June 2 after the Taliban threatened retaliation if the Afghan government executes Taliban prisoners in revenge for this week's devastating truck bombing in Kabul.

Media have reported that President Ashraf Ghani has signed orders to execute 11 Taliban and affiliated Haqqani network militants on death row, despite the Taliban's denial that it was involved in the bombing that killed at least 90 people and wounded hundreds on May 31.

Responding to the media reports, the Taliban warned the Afghan government against harming any of the prisoners even as many protesters in Kabul demanded the executions and other moves by the government to protect the public in demonstrations in Kabul on June 2.

The Taliban threatened "harsh exemplary attacks" in a statement on its website, including the killing of foreign hostages it holds, if the government executes the 11 prisoners.

The Taliban currently is holding two American University of Afghanistan professors, an American and an Australian who were kidnapped last year.

The university on June 2 pleaded with the Taliban to release Kevin King and Timothy Weeks, saying they "are innocents. Both came here to teach young Afghans, helping them to contribute to the rebuilding efforts of Afghanistan."

The Taliban is also holding Canadian backpacker Joshua Boyle and his American wife, Caitlan Coleman, who had two sons in captivity after being kidnapped in Afghanistan in 2012.

The government's reported move toward executing the Taliban prisoners reflects the conclusion of Afghanistan's main intelligence agency, the National Directorate for Security, that the Haqqani network, a group affiliated with the Taliban, was responsible for the bombing, AFP and Reuters reported.

The news agencies said the government has drawn up a list of prisoners from the groups to be executed based on that conclusion.

Some protesters on June 2 were demanding the execution specifically of Anas Haqqani, son of the Haqqani network's founder, who has been held by the Afghan government since 2014.

But a government source told AFP that Anas was not among the 11 prisoners the government planned to execute.

With reporting by AFP and Reuters