Nigeria's intelligence agency says it has arrested nine alleged Boko Haram extremists plotting attacks on Abuja, the capital, over the festive season.

Saturday's statement follows a warning Friday from the U.S. Embassy that extremists may be planning attacks on hotels favored by Westerners.

The Department of State Security says one of the nine men arrested was carrying out surveillance of a "high-profile hotel." It says all nine were detained in the past month and had infiltrated the capital in central Nigeria from the country's northeast where most extremist attacks occur.

Boko Haram has claimed previous suicide and car bomb attacks that have killed hundreds in Abuja. Their suicide bombings, village raids and kidnappings continue in the northeast.

Nigeria's 6-year Islamic uprising has killed 20,000 people and spread to neighboring countries.