Afghanistan's Taliban claimed responsibility for an attack on a base that killed two American Marines, saying it was a response to the insults to the founder of Islam.
Hundreds of Muslims took to the streets of Australia's largest city, some throwing rocks and bottles in clashes with police. Some carried placards reading "Behead all those who insult the Prophet".
About 80 Islamist militants were arrested in Paris while trying to demonstrate outside the US Embassy near the Champs Elysees, French police sources said.
Saturday was, however, relatively calm after at least nine deaths in the Muslim world on Friday during protests and attacks on American and other Western embassies.
President Barack Obama, leading a ceremony on Friday to honour the US ambassador to Libya and three other Americans who died in an attack on the US Consulate in Benghazi on Sept. 11, vowed to "stand fast" against the violence.
"The United States will never retreat from the world," he said.
The Pentagon rushed to bolster security at missions abroad.
The US state department on Saturday also urged American citizens to avoid Sudan's restive Darfur, Blue Nile and Southern Kordofan regions.
Libyan authorities said they had identified 50 people who were involved in the attack in which ambassador Christopher Stevens died.
In an interview aired on Saturday on NBC's Nightly News, Libyan President Mohammed Magarief was quoted as saying that foreigners along with Libyans were involved in the attack on the consulate in Benghazi. He added there were 10 suspects in custody.
Saudi Arabia's Grand Mufti, Sheikh Abdulaziz bin Abdullah Al al-Sheikh, denounced the attacks while urging governments and international bodies to criminalise insults against prophets.
He described the short film as "miserable" and "criminal," but said attacks on the innocent and on diplomats were "a distortion of the Islamic religion and are not accepted by God".
Free speech laws
The video, circulating on the internet under several titles including Innocence of Muslims.
"We were attacked by Obama, and his government, and the Coptic Christians living abroad!" shouted one long-bearded Muslim protester outside the US Embassy in Cairo on Friday.
Egyptian protesters gather around a burning vehicle in downtown Cairo, Egypt. AP
In the Los Angeles suburb of Cerritos, Nakoula Basseley Nakoula, 55, who has denied involvement in the film in a phone call to a Coptic Christian bishop, was ushered out of his home and into a waiting car by sheriff's deputies, his face shielded by a scarf, hat and sunglasses.
He was voluntarily interviewed by federal probation officers and left about 30 minutes later, a police spokesman said.
US officials have said authorities are not investigating the film project itself, and that even if it was inflammatory or led to violence, simply producing it cannot be considered a crime in the United States, which has strong free speech laws.
A statement posted on a website used by al Qaeda in the Arabian Peninsula called on Muslims to "follow the example of Omar al-Mukhtar's descendants ( L ibyans), who killed the American ambassador".
"Let the step of kicking out the embassies be a step towards liberating Muslim countries from the American hegemony," the group said.
Hundreds of mourners in the Yemeni capital, Sanaa, attended the funeral on Saturday of a young protester shot to death when riot police battled a crowd attacking the US Embassy on Thursday.