ISLAMABAD — At least one policeman has been killed and more than 50 injured, Pakistan’s authorities say, as officials try to stop thousands of opposition protesters reaching Islamabad.

Scores of supporters of jailed former PM Imran Khan have been arrested and the capital is under lockdown for a second day.

Khan has been detained for more than a year on various charges, but remains hugely popular despite his legal troubles.

His wife, Bushra Bibi, told supporters on Monday the march would continue until her husband was freed.

Roads to D Chowk – a key point in central Islamabad near government buildings, the Supreme Court and parliament – remain blocked with shipping containers to keep protesters at bay. The streets are lined with coaches that have carried police from around the country to the capital.

Paramilitaries in riot gear are lined up, water cannon ready, but on Monday the atmosphere was calm as protesters were yet to reach the city.

As news circulated that the protesters were on the move, the police began to close more streets and move some of their officers around the city.

Some internet services have been suspended. Schools and colleges have been shut because of fears of violence.

Imran Khan’s party has been protesting for months. The latest rally came after he issued a "final call" to his supporters, urging them to stay in the capital until their demands were met.

They are also calling for the overturning of election results they say were rigged – a claim disputed by the government.

The march, which began on Sunday, has seen police using tear gas against protesters, who have responded by pelting officers with stones.

Police told the BBC on Monday that 139 people had been arrested.

Khan’s wife is one of the leaders of the main convoy.

"Until Khan comes to us, we will not end this march," Bushra Bibi told crowds as the rally neared the capital.

"I will stand till my last breath and you have to support me. This is not just about my husband but about this country and its leader," she said.

Bushra Bibi was sentenced alongside Khan in January, but released on bail in late October.

Although Khan has now been behind bars for more than a year, he is still the dominant force of Pakistan’s opposition politics.

He was voted out of power by parliament in 2022 amid reports that he had fallen out with the country's powerful military.

He denies all the charges against him, which range from corruption to instigating violence to getting married to Bushra Bibi illegally.

In February’s general election, his party was banned from standing. Independent candidates backed by the PTI unexpectedly won the most seats – but not enough to form a government.

Khan accused the two parties now in government – the PML-N and PPP – of stealing the election. The authorities deny accusations of vote tampering. — BBC