Protesters have attacked Western embassies in Tunisia, Yemen and Sudan, as a wave of demonstrations against an anti-Islam film swelled and swept across much of the Muslim world after Friday prayers.
The US embassy was the common target while the UK and German embassies in Sudan were stormed by angry mobs.
In Tunis, the Tunisian capital, crowds scaled the US embassy walls and set fire to trees within the compound.
In Khartoum, the Sudanese capital, protesters broke into the US embassy grounds. Earlier, they had stormed the UK and German embassies.
Al Jazeera's Harriet Martin, reporting from Khartoum, said: "I have seen buses going past towards the US embassy in Khartoum, with riot police also following.""The Sudanese authorities are taking things very seriously as they have deployed many, many riot police in the direction of the US embassy.
Protesters also clashed with police in Yemen, where one person died and 15 were injured the day before when the US embassy compound was stormed.
"Today is your last day, ambassador", and "America is the devil", some placards said.
Crowds also gathered against the California-made film for the second day in Malaysia, Bangladesh and Iraq.
Demonstrators furious at a film trailer they say insults the Prophet Muhammad also clashed with police near the US embassy in Cairo.
In Gaza, thousands of people rallied at demonstrations in Gaza City and the southern town of Rafah, a day after the ruling Hamas party urged citizens to turn out for protests after Friday prayers.
Protesters waved the flags of the Hamas and Islamic Jihad movements, and set fire to American flags, chanting "Death, death to America, death, death to Israel".
The film was blamed for an attack on the US consulate in Libya's eastern city of Benghazi that killed the US ambassador and three other Americans on Tuesday, the anniversary of the September 11, 2001, al-Qaeda attacks on the United States.
Al Jazeera's Hoda Abdel Hamid, reporting from Benghazi, said: "There is a lot of tension in Benghazi people are confused, they want to protest, but after what took at the US consulate, people are apprehensive, Libyan authorities still believe it was a planned attack at the embassy".
In Nigeria, where radical Islamist sect Boko Haram has killed hundreds this year in an insurgency, the government put police on alert and stepped up security around foreign missions.
Challenge for Obama
The protests present US President Barack Obama with a new foreign policy crisis less than two months before seeking re-election and tests Washington's relations with democratic governments it helped to power across the Arab world.
Obama has vowed to bring those responsible for the Benghazi attack to justice, and the United States sent warships towards Libya which one official said was to give flexibility for any future action.
Egypt has said the US government, which has condemned the film, should not be blamed for it, but has also urged Washington to take legal action against those insulting religion.
The ruling Muslim Brotherhood said it would organise marches and sit-ins in front of mosques - but none outside the US embassy in Cairo.
After talks with Italian leaders in Rome, President Mohammed Morsi reiterated his government's determination to protect foreign diplomats on its soil. He also condemned the film as unacceptable.
In Libya, authorities said they had made four arrests in the investigation into the attack that killed Ambassador Christopher Stevens. US officials said it may have been planned in advance - possibly by an al-Qaeda-linked group.
Hillary Clinton, the US secretary of state, said Washington had nothing to do with the crudely made film posted on the Internet,which she called "disgusting and reprehensible", and the Chairman of the US Joint Chiefs of Staff called a Christian pastor in Florida to ask him to withdraw his support for it.
Egypt's Coptic Orthodox church has condemned what it said were Copts abroad who had financed the film.