The details of any threat are unknown but residents of the Federal Capital Territory (FCT) have been on high alert since Sunday after several Western embassies changed their travel advisories citing an elevated risk, particularly in Abuja.
In a statement late on Thursday, Nigerian police instructed: “all strategic police managers in charge of commands and tactical formations within the country to beef up security in their respective jurisdictions, especially in the FCT.”
The Inspector General of Police Usman Alkali Baba said “all emergency numbers” should be activated to help ensure “a 24/7 prompt response with combatant officers and men on standby.”
He urged residents of the city of six million “to remain vigilant and report any suspicious or abnormal occurrence and persons to the police.”
The statement came as the US State Department on Thursday ordered the departure of non-critical diplomatic staff and their families from Abuja.
“Terrorists may attack with little or no warning,” targeting malls, markets, hotels, restaurants, bars or schools, the State Department said in its country summary for Nigeria, but did not give further details.
The United States, Britain, Australia and Canada had issued warnings last weekend, although the three latter countries had not ordered any evacuation of staff or their families as of Friday morning.
On Thursday, Jabi Lake Mall, a major shopping centre in Abuja was temporarily shut down for unspecified security reasons.
The government said that Nigerians and foreigners in the country “should continue to be alert but must not panic.”
“I can assure all that our military and other security agencies have continued to do everything possible to secure and protect Nigerians and foreigners living in Nigeria,” said the Minister of Information and Culture Alhaji Lai Mohammed.
“Terrorists have been hard hit and put on the run,” he said during a press conference on Tuesday.
Nigerian troops are deployed throughout the West African nation of some 200 million people, fighting against Islamist insurgents and heavily armed criminals.
Jihadists generally operate in the northeast of the country, far away from the capital, though they have small cells in other parts of the country.
The last time one of the groups — Boko Haram — attacked the city centre was in 2014.
But the Islamic State West Africa Province, linked to the Islamic State group, has claimed several attacks around the FCT in the past six months, including a mass jailbreak in July.
The incident in Kuje, in which more than 400 inmates including dozens of suspected jihadists escaped, prompted President Muhammadu Buhari to say he was “disappointed” with his intelligence services.
Analysts have warned that insecurity could worsen with the start of political campaigning for the general election to replace Buhari next year.