By Asif Shahzad, Gibran Naiyyar Peshimam and Charlotte Greenfield ISLAMABAD (Reuters) -At least six people, including four paramilitary soldiers, were killed on Tuesday during clashes near Pakistan's parliament between security forces and protesters who are demanding the release of former Prime Minister Imran Khan.

Pakistan police said Wednesday they had arrested nearly 1,000 protesters who marched on the capital demanding the release of jailed ex-prime minister Imran Khan, after crowds were evicted from the city centre in a sweeping security crackdown.

Four members of Pakistan’s security services were killed as thousands of former Prime Minister Imran Khan's supporters broke through government barricades and clashed with law enforcement in the country's capital Islamabad.

The country’s Interior Minister Mohsin Naqvi ruled out any negotiations, while Prime Minister Shehbaz Sharif blamed protesters for the soldiers’ deaths

Security forces in Pakistan were seen pushing a protester off a 25ft-tall tower of shipping containers during a demonstration that saw nearly 1,000 people arrested. The incident captured on camera and widely circulated on social media happened as thousands of supporters of former prime minister Imran Khan converged in Islamabad to demand his release from prison.

Security forces clashed with protesters near Pakistan's parliament on Tuesday as hundreds of supporters of jailed former Prime Minister Imran Khan demanded his release in demonstrations the government said have killed four paramilitary troops.