Supporters of Pakistan's imprisoned former prime minister, Imran Khan, and security forces have clashed in the capital Islamabad. At least four security personnel have been killed and dozens of people injured.

Thousands of Khan's political party members and supporters have been carrying out a massive protest march towards the capital since Sunday. They are seeking Khan's release.

Khan was ousted from power in 2022. Later, he was found guilty of corruption and other charges--all of which he and his party have denied.

Pakistan's Interior Ministry announced the death of the security personnel on Tuesday.

Prime Minister Shehbaz Sharif condemned the bloodshed, saying "it is not a peaceful protest, but extremism."

The government has enforced a security lockdown. Major roads into the capital have been blocked. And mobile and Internet services have been partially suspended.