Nigeria on Friday said it had stepped up security and urged the public to remain vigilant but calm after the United States and Britain warned of a high “terror” threat in the capital Abuja.

Without providing further details on a specific threat, the US on Thursday ordered the families of diplomats to leave Abuja, citing an “increased risk of terrorist attacks”.

Residents in the Federal Capital Territory (FCT) have been on high alert since Sunday when several western embassies changed their travel advice, pointing to an increased risk of attack in Abuja.

Nigerian troops fight jihadist insurgents mainly in the northeast, although small cells exist in other parts of the country.

Militants linked to the Islamic State group have called for several attacks near the capital over the past six months, including a mass prison break in July.

The Kuje incident, in which more than 400 inmates escaped, including dozens of suspected jihadists, had prompted Buhari to say he was “disappointed” with his intelligence services.

But since then “security measures in and around the FCT have been strengthened,” according to a statement from President Muhammadu Buhari’s office on Friday, which referred to “the increased surveillance and interception of terrorist communications.”

“Terror is a reality worldwide. However, that does not mean an attack in Abuja is imminent,” she added.

The President said he had given “assurances that the government has the security situation under control”.

“Attacks are thwarted. Security agents proactively remediate threats to keep citizens safe—much of their work is invisible and necessarily confidential.”

While ordering “extra precautions to be taken,” Buhari said that “recent changes in travel advice from the US and UK governments should not be cause for panic.”

On Thursday, Nigerian Police instructed “all strategic police managers responsible for commands and tactical formations within the country to reinforce security in their respective jurisdictions, particularly in the FCT.”

Inspector General of Police Usman Alkali Baba said “all emergency numbers” should be activated to ensure “quick 24/7 response with ready officers and men on duty”.

The statement came as the US State Department ordered diplomatic officials to leave Abuja.

A statement on Thursday first said that non-emergency government employees and their families had been asked to leave the country. On Friday, the State Department clarified that the evacuation order applies to families, not employees, who have been authorized but not instructed to leave.

“Terrorists may attack with little or no warning” targeting malls, markets, hotels, places of worship, restaurants, bars or schools, the Foreign Ministry said in its country summary for Nigeria.

The United States, Britain, Australia and Canada had issued warnings over the past weekend, although the latter three countries had not ordered evacuations of employees or their families as of Friday.

Separately, this week the US warned of a possible “terrorist attack” in South Africa’s largest city, Johannesburg.

Some European embassies and international organizations have not updated their risk assessments or travel advice for Nigeria.

“We don’t have a crisis to deal with, we deal with the panic,” a senior security manager at an international organization based in Abuja told AFP, asking not to be identified.

“We don’t know what the motive (behind the US evacuation) is. We are taking some precautions/actions but activities are normal,” he added.

On Thursday, Jabi Lake Mall, a large shopping mall in Abuja, was temporarily closed due to unspecified security concerns.

Nigeria’s military is few and far between, with soldiers stationed in most parts of the West African nation of about 200 million people.

The last time a jihadist group – Boko Haram – attacked the city center was in 2014.

In addition to the ongoing terrorist threat, the capital is also surrounded by states with rampant banditry – gangs of gunmen who kidnap and kill without ideological motivation.

Analysts have warned that uncertainty could deepen as political campaigning begins for the general elections set to replace Buhari next year.