Pakistan security forces fired volleys of tear gas and rubber bullets Tuesday at thousands of protesters calling for the release of jailed ex-prime minister Imran Khan, after they defied a police lockdown to march inside the nation's capital.

Supporters seeking the release of imprisoned Pakistani former premier Imran Khan on Tuesday broke through a ring of shipping containers locking down the capital Islamabad, battled police, and ignored a government threat to respond with gunfire.

Supporters of the ex-prime minister marched toward Islamabad, the capital. Clashes with the police left at least one officer dead, the authorities said.