The United States on Thursday ordered its non-essential diplomats and their families to leave the Nigerian capital, Abuja, due to the "escalating risk of terrorist attacks," the State Department said in a statement.

On Tuesday, Washington allowed them to leave the city if they wished to do so.

Recently, several Western embassies recommended their nationals to limit their movements in the country.

Residents of Abuja and surrounding areas, including Western diplomats, are increasingly concerned about the insecurity after a mass escape last July from Kogi prison on the outskirts of the capital.

At that time, more than 400 detainees escaped, including dozens of suspected ISIS operatives.

The organization claimed responsibility for the attack, which enabled them to escape.

 The police and army announced the reinforcement of security measures in and around the capital, but Abuja is surrounded by mountainous and forested areas that are difficult to secure.

The Nigerian authorities confirmed "taking all necessary precautions" following several Western warnings.

Militants often launch attacks in parts of northeastern Nigeria, far from the federal capital, but there are cells present in other parts of the country.


Schools and places of worship

And last Sunday, the United States and Britain warned of the possibility of a terrorist attack in the Nigerian capital, Abuja, targeting in particular government buildings, places of worship, schools and more.

"There is an increased potential for terrorist attacks in Nigeria, specifically Abuja," the US Embassy in Nigeria said.

It added that shopping malls, law enforcement facilities and the headquarters of international organizations were among the places at risk.

In an alert to citizens of Nigeria, the embassy said that "the US embassy will reduce its services until further notice."

The UK government has also urged its citizens in Nigeria to exercise caution due to the "increased possibility of a terrorist attack in Abuja".

"The attacks can be indiscriminate and may affect Western interests as well as places visited by tourists," she added.