At least one protester has been killed as clashes break out between security forces and angry demonstrators condemning a recent US-made anti-Islam film near Pakistan’s US consulate building in Karachi.
Police forces reportedly opened fire and used tear gas to disperse the crowd, injuring another 20 protesters.
The number of casualties and injuries are likely to increase.
Local sources say smoke is visible around a building near the US consulate.
Demonstrations are also being held in Quetta, the capital of the southwestern Balochistan Province, with people burning the US flag. Protesters have also gathered in Peshawar and Lahore.
On Friday, Pakistanis gathered outside the US Embassy in Islamabad, demanding the government to expel the US diplomats.
Pakistan has blocked access to the film’s trailer on the internet.
Outrage and anti-US sentiment is growing across the Muslim world over the obscure movie that insults Islam's Prophet Mohammad (PBUH).
Following the release of the sacrilegious film, protests have erupted across the region, with demonstrators gathering at US embassies in their countries.
The protests have led to deadly attacks on the US diplomatic buildings in Libya, Egypt, and Yemen.
Demonstrators in Iran, Sudan, Egypt, Yemen, Tunisia, Australia, Afghanistan, Pakistan, Malaysia and many other countries have poured into the streets to condemn the blasphemous movie.
On Tuesday, US Ambassador to Libya Christopher Stevens and three other consulate staff members were killed in Benghazi after clashes involving a group of angry demonstrators near the consulate building.