THE GUNMEN WHO killed 50 people at a Catholic church in southwestern Nigeria opened fire on worshippers both inside and outside the building, in a coordinated attack before escaping the scene, authorities and witnesses said on Monday.

Although Nigerian security forces have not yet identified who carried out Sunday’s attack on St Francis Church in the town of Owo in relatively peaceful Ondo state, analysts suggested they came from elsewhere in the country, which is plagued by violence from various armed groups, kidnappers and extremists.

No one has claimed responsibility for the killings, in which children were among the dead and the gunmen used some kind of explosive.

Scores of people were wounded, although an exact number was not released by overwhelmed hospital workers.

“The attack is undoubtedly terrorist in nature, and the scale and brutality suggests it was carefully planned rather than impulsive,” said Eric Humphery-Smith, senior Africa analyst at Verisk Maplecroft risk intelligence company.

State police commissioner Oyeyemi Oyediran said security forces, including the military, pursued the attackers “but unfortunately, we could not catch up with them”.

Nigeria, which is Africa’s most populous country with 206 million people, has grappled for more than a decade with an insurgency in the north east by Islamic extremist rebels of Boko Haram and its offshoot, the so-called Islamic State West Africa Province.

The extremists have killed more than 35,000 people by a UN count.

Ondo, however, has long been considered one of the safer states in the country.

Sunday Adewale, who works in the palace of the local chief, said the gunmen used the element of surprise to their advantage.

“Everybody felt relaxed and had gone to church,” he said. “Within 30 minutes, they did what they wanted and went away.”

The attack came as worshippers were celebrating the feast of Pentecost, an important Catholic post-Easter holiday.

Bishop Jude Arogundade said some gunmen entered the church while others stayed outside to shoot anyone who fled.

Steven Omotayo, who lives nearby, heard the gunshots and went to the scene.

“I saw a lot of dead bodies, both young and old, even children,” he said. “The people came in and started shooting from the gate.”

He said the church has three entrances and the main entrance was said to have been locked, making it difficult for many to escape.

“They were just shooting. If they see anyone trying to escape or stand up, they will just shoot the person,” he said. “Everybody standing was bombarded with bullets.”

Many Nigerians expressed shock and anger over the attack in Owo, a small town of traders and government workers 30 miles from the Ondo state capital of Akure.

The central location of the church raised questions as to how the gunmen got there unnoticed.

Workers at the Federal Medical Centre in Owo struggled to treat scores of wounded from the attack. The Nigeria Medical Association directed all available doctors in the region to help.

Some of the wounded were in a “very bad state” and needed surgery, according to a doctor there.

“I have attended to a good number of casualties, but what I saw yesterday was far beyond whatever I have seen before in my life,” the doctor said.

“This calamity befell all age grades, from toddlers to the old ones.”