Thousands of opposition protesters have converged on Pakistan's heavily barricaded capital, demanding the release of jailed former Prime Minister Imran Khan.
The convoy, targeting a square in central Islamabad, has already clashed with security forces, who fired tear gas and rubber bullets at protesters to try to disperse them.
According to the prime minister's office, four paramilitaries were killed in a hit-and-run, blamed on Khan's supporters. This has not been independently verified.
Khan has been held in prison for more than a year and faces a series of charges and sentences that he says are politically motivated.
Even behind bars, the former cricket star has proven to be a powerful player in Pakistani politics. In the February elections, his Pakistan Tehreek-e-Insaf (PTI) party, which had been forced to field independent candidates, emerged as the largest bloc.
However, they failed to gain a majority and their rivals united to form a new government.
As a result, protesters are also calling for the annulment of election results they believe were rigged – a claim disputed by the government.
It was Khan who called on his supporters to take to the streets this weekend, issuing a “final appeal” and asking them to stay in the capital until their demands are met.
This was after authorities banned public gatherings.
The government responded by blocking Islamabad's streets with shipping containers and bringing in police from across the country by bus.
Pakistan's interior minister said protesters had been offered an alternative venue but declined.
The unrest led to the suspension of some internet services, while schools and colleges were closed due to fears of violence.
After days of traveling, the demonstration has now reached the outskirts of the city center.
