ABUJA, Nigeria (AP) — Residents in Nigeria’s capital city, Abuja, were on high alert and avoided some places on Monday, a day after the U.S. and U.K. issued terror alerts about possible attacks in the city.

The Department of State Services, which is Nigeria’s secret and intelligence police, called for calm and advised that “necessary precautions are taken” to prevent such attacks.

The warnings came amid heightened concerns over Nigeria’s security woes with, frequent violent attacks targeting remote communities in various parts of the country’s northern region.

Nigeria's security forces have in the past warned of similar attacks in Abuja, which is also in the north. It was, however, spared most such incidents until July, when nearly 1,000 inmates escaped during a jailbreak carried out by Islamic State-backed extremists.

On Sunday, the U.S. Embassy issued an alert for “an elevated risk of terror attacks” in the city, saying that possible targets include government buildings, places of worship and other public places.

“The U.S. Embassy will offer reduced services until further notice,” the mission said in a statement, urging citizens to avoid all nonessential movements and crowds.

The U.K. mission in Nigeria also took a similar step and restricted entry to the British High Commission in the city in an updated terrorism alert.