Dhaka, Oct. 5 -- Thousands of supporters of jailed former Pakistan prime minister Imran Khan are marching towards Islamabad, demanding his release amid growing concerns over his health in prison.

The march began on Sunday in Lakki Marwat, around 275km from the Pakistani capital, and paused overnight, the BBC reported. It is expected to resume around midday on Monday.

Khan's Pakistan Tehreek-e-Insaf (PTI) had originally planned the march for last week but postponed it to allow talks with the government. The negotiations subsequently ended without an agreement.

Sohail Afridi, chief minister of the PTI-ruled Khyber Pakhtunkhwa province, expects the march to reach a town about 80km west of Islamabad by Thursday.

Authorities have meanwhile...