Russian President Vladimir Putin said Thursday the Middle East was at risk of descending into "chaos" following a deadly attack on the U.S. mission in Libya and incidents in Egypt and Yemen.

"We are afraid that the region may descend into chaos, which is essentially what is happening already," he said in comments broadcast on state television from his summer residence in the Black Sea resort of Sochi.

U.S. Secretary of State Hillary Clinton on Thursday condemned an amateur anti-Islam film which has sparked violent Middle East protests, stressing the U.S. government had nothing to do with it.

"To us, to me personally, this video is disgusting and reprehensible. It appears to have a deeply cynical purpose, to denigrate a great religion and to provoke rage," Clinton said.

Libya has made several arrests over an attack on the U.S. consulate in Benghazi that killed the ambassador and three other U.S. nationals, the deputy interior minister told AFP on Thursday.

"The interior and justice ministries have begun their investigations and evidence gathering and some people have been arrested," Wanis al-Sharef said.

About 100 protesters burnt the United States' flag and chanted slogans in the Bangladeshi capital Dhaka on Thursday to demonstrate against an anti-Islam Internet film.

The demonstrators, mostly students at Islamic seminaries, hit the flag with shoes before setting it ablaze in front of the Baitul Mokarram Mosque, Bangladesh's biggest mosque.

China's official news agency said Thursday the assault that killed the U.S. ambassador to Libya highlighted an "arrogant" Washington's "flawed" Middle East strategy, in unusually outspoken comments.

In a strongly worded commentary Xinhua said the violent attack, which has been condemned by governments around the world including China's, showed the need for Washington to reconsider its policies in the region.

Libya has set up an independent judicial committee to probe an attack on the U.S. consulate in Benghazi in which four Americans including the ambassador were killed, a spokesman said on Thursday.

"All measures are being taken. An independent judicial committee has been set up to carry out an inquiry," Abdelmonem al-Horr, spokesman for the Libyan interior ministry's security commission, told AFP.

Police used tear gas as they clashed on Thursday with a stone- and bottle-throwing crowd protesting outside the U.S. embassy in Cairo at a film mocking Islam, witnesses and the interior ministry said.

The health ministry said 13 people were injured during sporadic clashes through the night outside the embassy, where on Tuesday thousands of protesters tore down the Stars and Stripes and replaced it with a black Islamic flag.

Libya agreed on a decision taken by United Nations chief Ban Ki-moon to appoint Lebanon's ex-Information Minister Tarek Metri as U.N. special envoy to Tripoli and head of the U.N. Support Mission in Libya (UNSMIL).

Metri will succeed British Ian Martin as head of UNSMIL, whose tenure will end on October 14, a Libyan diplomat told An Nahar newspaper on Thursday.

The Stars and Stripes atop the White House was lowered Wednesday after President Barack Obama ordered all flags on government buildings to half mast to honor Americans slain in Libya.

"I hereby order that the flag of the United States shall be flown at half-staff at the White House and upon all public buildings and grounds," Obama said in a proclamation.

Libyan security guards were killed and wounded trying to defend U.S. ambassador Chris Stevens during the attack in Benghazi in which the U.S. diplomat died, a Libyan U.N. envoy said Wednesday.

Ibrahim Dabbashi, Libya's deputy U.N. ambassador, told reporters that up to 10 Libyan security personnel were casualties of the attack on Tuesday. "Some of them have been killed at the start of the attack," he said.