Al-Qaida in the Islamic Maghreb issued a statement Tuesday calling last week's assassination of Stevens "the best gift you (can) give to this arrogant and unjust administration," CNN reported.
"We encourage all Muslims to continue to demonstrate and escalate their protests ... and to kill their (American) ambassadors and representatives or to expel them to cleanse our land from their wickedness," the statement said.
Libya has taken steps to arrest those believed responsible for last week's consulate attack in Benghazi that killed Stevens and three other Americans. The FBI is also investigating the attack.
A Taliban-allied insurgent group claimed responsibility Tuesday for a suicide attack that killed 12 people in Afghanistan. The attack was in response to the film the group said.
Hezb-e-Islamic Gulbuddin, a group allied with the Taliban, said a 22-year-old woman drove a car packed with explosives into a van on a road leading to Kabul International Airport.
Eleven others were wounded in the attack, the Afghan interior Ministry said.
Protests linked to the online trailer of an anti-Islam film continue.
The leader of Lebanon's Hezbollah movement called for additional protests to express outrage over the U.S.-made film that mocks Islam and the Prophet Muhammad.
"Prophet of God, we offer ourselves, our blood and our kin for the sake of your dignity and honor," Hassan Nasrallah told thousands of supporters in a rare public appearance at a rally in a Shiite suburb south of Beirut.
"The U.S. should understand that if it broadcasts the film in full it will face very dangerous repercussions around the world," Nasrallah said, adding their anger should not be directed at Christians but at the United States and Israel, even though the film, "Innocence of Muslims," was allegedly produced by a radical Coptic Christian.
The crowd chanted "Death to Israel" and "Death to America," British newspaper The Guardian reported.
In Washington, the U.S. State Department said the United States' heavily fortified embassy in Beirut was in no immediate danger.
Governments, Nasrallah said, must create laws criminalizing "insults of the three world religions," referring to Islam, Christianity and Judaism, al-Jazeera reported.
"The world does not understand the breadth of the humiliation," he said at the rally.
"The world must understand the depth of our bond with our prophet," Nasrallah said, calling the video the "worst attack ever on Islam."
His public appearance was his fifth in six years and his first full speech in person to thousands of supporters since 2008.
Nasrallah is widely understood to fear assassination by Israel, which along with the United States considers the Hezbollah Lebanese political and paramilitary organization a terrorist group.
Nasrallah, 52, became Hezbollah's leader after Israel assassinated previous leader Abbas al-Musawi in 1992.
In Benghazi, Libya, a spokesman for the Islamist brigade suspected in the military-style attack on the U.S. Consulate Sept. 11 denied involvement in the attack that led to the deaths of Stevens and three other Americans.
"We categorically deny we were there," Youssef el-Gehani, spokesman of the Ansar al-Shariah brigade, told The Guardian.
The brigade is a loosely structured Islamist militia group that advocates a strict Islamic moral code and religious law across Libya.
"American policies target some of the most sacred elements of our religion, so you should expect a reaction," he told The Guardian. "The embassy [U.S. consulate] knew how sensitive it was to have that film -- they should have evacuated the embassy."
He said if Washington wants respect from the Arab world, "it should avoid spilling blood in places such as Syria and Afghanistan, and avoid insulting the prophet."
Anti-American violence raged in Kabul, Afghanistan, with hundreds taking to the streets, burning tires and a car and attacking police and a U.S. base with stones.
In Pakistan, Prime Minister Raja Perez Ashraf ordered the suspension of YouTube over the "blasphemous" film as thousands of people shouting anti-American slogans took to the streets in three major cities. At least two protesters were killed, authorities said.
Indonesian police fired tear gas and water cannons to disperse hundreds of demonstrators outside the U.S. Embassy in Jakarta.
Iran Supreme Leader Ayatollah Ali Khamenei was quoted on state TV as saying Western leaders must prove they weren't "accomplices" in the film.
In Egypt, two well-known figures faced legal action for broadcasting a 2-minute clip of the film on an Egyptian TV station.
Sheik Khaled Abdallah, an ultraconservative TV anchor, and Nader Bakkar, spokesman of the Al-Nour Party, formed by ultraconservative Salafis, were accused of instigating the violence that led to the storming of the U.S. Embassy in Cairo Sept. 11.