Indonesian police said Monday anger at a U.S.-made anti-Islam film was among the motives behind failed terror attacks against foreign targets.

Last week, the anti-terror squad arrested 11 people suspected of planning attacks on domestic and foreign targets, including the U.S. Embassy and a site near the Australian Embassy.

National police spokesman Brig. Gen. Boy Rafli Amar said based on seized documents and other information, anger at the American-made movie denigrating Islam's Prophet Muhammad was one of the reasons behind the planned attacks. The movie caused deadly outrage across the Middle East when it went online in September.

Police seized a number of bombs, explosive materials, a bomb-making manual and ammunition, along with a small gas cylinder filled with highly explosive material during the Friday and Saturday raids in four cities, including the capital Jakarta.

The U.S. Embassy in Jakarta has urged U.S. citizens in Indonesia to avoid large crowds and other gatherings that might turn violent.

"At first, they wanted to attack (security) officers ... and based on documents and other information, the foreign targets were linked with the film which insulted Islam," Amar told a news conference.

He was referring to "Innocence of Muslims," that denigrates the Prophet Muhammad. At least 49 people, including the U.S. ambassador to Libya, were killed last month in violence linked to the film.

Indonesia, the world's most populous Muslim-majority nation, has been battling terrorists since the 2002 bombings in Bali, which killed 202 people, mostly foreign tourists.

Subsequent attacks have claimed more than 50 people, mostly Indonesians. The government has arrested more than 700 suspected terrorists and killed dozens more in an attempt to root out the militants.