ABUJA (Reuters) - Police in Nigeria, which faces an Islamist insurgent threat, ordered 24-hour security around all foreign embassies on Thursday after gunmen in Libya enraged over a film about the Prophet Mohammad killed the U.S. ambassador there.
The American embassy in Abuja issued an emergency warning to its citizens living in Nigeria, where radical Islamist sect Boko Haram has killed hundreds this year in an insurgency against the Nigerian government.
"Extremists may attempt to target U.S. citizens and other Westerners in Nigeria," the message on the embassy's website said. "The situation in the country remains fluid and unpredictable."
U.S. embassies in Yemen and Egypt were attacked by demonstrators on Thursday and U.S. warships headed to Libya after Tuesday's attack on the U.S. mission there that killed the ambassador and three other Americans.
Nigerian authorities fear an Islamist backlash, possibly after Friday prayers this week.
"The Inspector-General of Police (IGP), Mohammed Dahiru Abubakar, has placed all police formations across the federation on red alert," a statement from the Nigerian police said.
"The IGP has directed ... 24-hour water-tight security in and around all embassies and foreign missions in Nigeria as well as other vulnerable targets."
The Nigerian Islamist sect Boko Haram has killed hundreds of people this year as it aims to revive an ancient Islamic state in the modern West African country of 160 million people, split roughly evenly between Muslims and Christians.
Boko Haram bombed the offices of Nigerian newspaper This Day in April because of an article written years before about the Miss World beauty pageant and the Prophet Mohammad that they said was blasphemous to Islam.
The sect also carried out a suicide bombing on the United Nations building in the capital Abuja last year.
The attacks this week in several Arab states were by groups protesting against the anti-Islam film called the "Innocence of Muslims," by a U.S.-Israeli director which has been circulating online for weeks.
Muslim and Christian groups in Nigeria condemned the film but urged their followers to remain peaceful.
"We are appealing to the entire youth of our dear country Nigeria to remain law abiding resolute and focused so that some few individuals should not succeed in creating disharmony among us," the youth leader of the Christian Association of Nigeria (CAN) Diji Obadiah Haruna said in a statement.
"We should join hands in condemning such act of disrespect for our religious values."
Hundreds have been killed in recent years in periodic religious clashes in Nigeria's "Middle Belt", where the largely Christian south meets the mostly Muslim north. CAN often tries to temper potential sources of aggravation.
Islamist Egyptian President Mohamed Morsi said he backed peaceful protest but not attacks on embassies.
Egyptian Prime Minister Hisham Kandil said the U.S. government could not be blamed for the film, which many Muslims felt insulted the Prophet, but urged Washington to take action against its producers.
Additional reporting by Felix Onuah in Abuja and Garba Mohammed in Kaduna; Editing by Janet Lawrence