The influential leader of the Lebanon-based Shia Muslim militant group, Hezbollah, has called for fresh protests over an anti-Islam film.
The world needed to know Muslims "would not be silent in the face of this insult", Sheikh Hassan Nasrallah said.
Protests at many US diplomatic missions have been continuing over the amateur video, which was produced in the US.
Hundreds of protesters in Indonesia's capital faced off with police, throwing rocks and Molotov cocktails.
They burned the American flag and chanted anti-US slogans during the demonstration in Jakarta.
Police fired tear gas and made a number of arrests in response. One police officer was taken to hospital after being hit by a rock.
The US ambassador to Libya was among four Americans killed in the initial eruption of anger over the film.
But Libyan Interior Minister Fawzi Abdul Al has dismissed a claim on Sunday by the president of the national congress that 50 people have been arrested in connection with the deaths.
He said only four people had been detained so far, although up to 50 could be under investigation.
Among other developments:
• In Pakistan's Khyber Pakhtunkhwa province, the local press club was burnt down and government offices attacked in the Upper Dir district, with reports that one protester was killed in an exchange of fire with police, following the death of another protester on Sunday
• In Karachi, police set up street barriers and a security cordon around the US embassy amid reports that further rallies have been called
• Angry demonstrators in the Afghan capital Kabul fired guns, torched police cars and shouted anti-US slogans
• Hundreds of students called for the expulsion of the US ambassador in the Yemeni capital Sanaa, said the AFP news agency
In a speech broadcast on Hezbollah's al-Manar TV station, Sheikh Nasrallah called for a week of protests not only against American embassies, but also to press Muslim governments to express their own anger to the US.
He branded the video an "unprecedented" insult to Islam - worse, he said, than Salman Rushdie's novel The Satanic Verses and the cartoons of the Prophet Muhammad, which were published in a Danish newspaper in 2005.
"Those who should be held accountable, punished, prosecuted and boycotted are those directly responsible for this film and those who stand behind them and those who support and protect them," primarily the US, Sheikh Nasrallah said.
He named several days over the coming week on which demonstrations should take place around Lebanon - the first on Monday afternoon in a southern suburb of Beirut which is a Hezbollah stronghold.
Sheikh Nasrallah said the film aimed to cause strife between Muslims and Christians and applauded many protests so far for their focus on the US and Israel - which he said stood to gain from Muslim-Christian conflict - and not Christians.
Arab and Islamic governments should press for an enforceable international law banning insults to Islam and other religions, Sheikh Nasrallah argued - like laws which already existed to prevent anti-Semitism.
In a BBC interview, Tony Blair said the film was "wrong and offensive but also laughable as a piece of filmmaking - what is dangerous and wrong is the reaction to it".
The former UK prime minister, who now serves as a Middle East peace envoy, said the protests were ultimately about the "struggle of modernisation" under way in the region and not "some form of oppression by the West".
The obscure, poorly made film at the centre of the row, entitled Innocence of Muslims, insults the Prophet Muhammad.
The exact origins of the film are shrouded in mystery, although US authorities say they believe the film was made by Nakoula Basseley Nakoula, a convicted fraudster living in California who has since been questioned over his role.
The violence which killed the US envoy to Libya in Benghazi was followed by a string of attacks on US consulates, embassies and business interests across the Middle East and north Africa. British, Swiss, German and Dutch properties have also been targeted.
Al-Qaeda in the Arabian Peninsula has called for fresh attacks against Western embassies, describing the recent unrest as "a great event", and urging protesters to unite to "expel the embassies of America from the lands of the Muslims".