Thousands of supporters of a banned radical Islamist party have left the eastern Pakistan city of Lahore, clashing for a second straight day with police who lobbed tear gas into the crowd, a party spokesman and witnesses said.

The group began their journey on Friday with the goal of reaching the capital Islamabad to pressure the government to release Saad Rizvi, the head of the Tehreek-e-Labiak Pakistan party.

Rizvi was arrested last year amid demonstrations against France over the publication of caricatures of Islam’s Prophet Mohammed.

Pakistan Islamist Rally
Police fire tear gas to disperse the supporters of Tehreek-e-Labiak Pakistan (KM Chaudary/AP)

Violent clashes erupted between security forces and Islamists in Lahore, leaving at least two police and two demonstrators dead on Friday.

Sajid Saifi, a spokesman for Rizvi’s party, said supporters spent the night near the Ravi River bridge and in the early morning started again towards Islamabad amid heavy tear gas.

He said the huge crowd removed barricades and left the city limits but again faced security forces near the town of Kala Shah Kako.

Mr Saifi said “many” party supporters were injured by tear gas canisters as they attempted to leave Lahore.

Pakistan Islamist Rally
Police block the demonstrators in Lahore (KM Chaudary/AP)

Witnesses said the demonstrators were on foot but some vehicles took the injured to hospital and brought food and water.

Rizvi’s party gained prominence in Pakistan’s 2018 elections, campaigning on a single issue: defending the country’s blasphemy law, which calls for the death penalty for anyone who insults Islam.

It has a history of staging violent protests to pressure the government to accept its demands.