LAGOS (AFP) – A US warning of possible attacks on hotels in the capital city Abuja over the Muslim Eid al-Adha holiday was based on specific and credible information, an American diplomat said on Tuesday.

The diplomat who spoke on condition of anonymity would not say where the information regarding potential attacks by Islamist sect Boko Haram originated from, but said the US embassy had no choice but to warn its citizens.

Its unusually specific warning was issued in the wake of Friday’s coordinated gun and bomb attacks in Nigeria’s northeast claimed by Boko Haram that left some 150 people dead and was among the deadliest attributed to the group.

“We certainly took it very seriously,” the diplomat said of the information included in its advisory.

“Given the specificity and the credibility of the threat, we really felt we had no choice but to give our best counsel to Americans.”

Security has been put on high alert in the capital Abuja and no incidents have occurred. Abuja was last hit in August, when a suicide bomber attacked UN headquarters, killing 24 people.

Nigerian authorities have called the US warning about potential Abuja attacks “not news.” Nigerian newspaper ThisDay on Tuesday quoted a senior security chief who called the US warning “insulting to us as a nation.”

“The current threat of attack on the three hotels in Abuja is not news, and for over three months the security services have taken pro-active measures to protect the designated critical facilities and others,” national security adviser Andrew Azazi said in a statement on Monday.

The US diplomat said the embassy did not consult with the Nigerian government before issuing the statement, which warned that hotels and other locations in Abuja could be targeted over the holiday.

The embassy wanted to act as soon as possible to warn US citizens, he said.

“Following the recent Boko Haram, aka Nigerian Taliban, attacks in Borno and Yobe state, the US embassy has received information that Boko Haram may plan to attack several locations and hotels in Abuja, Nigeria, during the Sallah holiday,” the advisory said.

“Potential targets may include the Nicon Luxury, the Sheraton Hotel, and the Transcorp Hilton Hotel.”

Eid al-Adha was marked on Sunday, but Monday and Tuesday were also public holidays in Nigeria. The holiday is also referred to as Sallah in Nigeria.

The diplomat spoke of Boko Haram’s increasingly sophisticated and deadly attacks in Nigeria, Africa’s most populous nation and largest oil producer.

“I think it’s a trend which we’ve seen over the past year,” he said. “The group has become increasingly sophisticated, increasingly lethal.”

There has been intense speculation over whether the group has formed links with foreign extremists, such as Al-Qaeda’s north African branch.

The diplomat said there have been signs of individual links, such as Boko Haram members seeking training in foreign countries, but there has been no proof of operational ties.

“There’s no indication that Boko Haram has linked up operationally with any other extremists beyond Nigeria’s borders,” he said.

“The evolution of the group unquestionably though has made it clear that we need to step up our security procedures.”