ABUJA, Nigeria (AP) — Gunmen attacked two villages in the north-central region of Nigeria, killing at least 20 people, residents said Wednesday.

The attacks occurred in the early hours of Tuesday in Bagna and Erena, located in the Shiroro area of Niger state. Shiroro is about 250 kilometers (155 miles) or a four-hour drive from the capital, Abuja.

“They came on motorbikes and began shooting. It was a surprise attack, because it was in the early hours of the morning,” said Jibrin Isah, who lives in Erena.

Residents said that at least 20 people were killed, with more missing. However, local police said that only three people were killed.

“Unfortunately, two vigilante members and a driver from the joint security team lost their lives during the attack, while some others were injured,” Niger state police spokesperson Wasiu Abiodun said in a statement.

Residents said the attackers operated for hours, raiding homes and sending residents to flee to safety in neighboring communities.

“Those killed in the attacks were above 20,” Muhammad Tukur, a resident of Erena, told The Associated Press.

Nigeria, which is Africa’s most populous country, is battling a complex security crisis, especially in the north where there is a decade-long insurgency and several armed groups who kidnap for ransom.

Disputes over land and grazing between mostly Muslim Fulani herders and largely Christian farming communities frequently escalate into deadly clashes. Criminal gangs are also active.

The insurgency in the northeast has led to the death and displacement of many, according to the U.N.