Police in the Nigerian city of Maiduguri say a female suicide bomber, who they suspect was as young as 10 years old, carried out an attack that killed 19 people and injured 18 Saturday, Agence France-Presse reported. Borno state police representative Gideon Jubrin told reporters the 20 dead included “the female suicide bomber that detonated the improvised explosive device,” AFP said.

The blast happened at about 12:40 p.m. local time (7.40 a.m. EST) at the Monday Market in the Borno state capital. The market was packed with shoppers, the news agency noted. It was reportedly targeted twice in one week by female bombers last year.

“The girl was about 10 years old, and I doubt much if she actually knew what was strapped to her body,” Ashiru Mustapha, who was described as a civilian vigilante, told AFP. Mustapha said the girl was searched with a metal detector as she entered the market, “But, sadly, the explosion went off before she was isolated.”

Another witness to the attack told AFP the bomb blast “split the suicide bomber into two and flung one part across the road. Among the dead are two vigilantes who were searching the girl,” she said. “I am pretty sure the bomb was remotely controlled.”

AFP quoted a Red Cross official, who declined to give his name, as saying his organization had taken “10 bodies to the mortuary at the [Borno] State Specialist Hospital.” He added, “Many people sustained life-threatening injuries.”

An attack at the market Dec. 1 killed more than 10 people, and another there the previous week killed more than 45, the Telegraph reported, citing agency accounts.

Boko Haram did not immediately claim responsibility for the latest attack, but the Islamist militant group has notably been employing women to carry out its attacks recently.

Vice News reported last month that Boko Haram began enlisting women as suicide bombers in April. Since then, there have been 15 attacks or attempted attacks by Boko Haram female suicide bombers, who have been given a larger role in the violent insurgent movement, according to Jacob Zenn, an analyst of African and Eurasian affairs for the Jamestown Foundation, a Washington-based research institute.

Zenn said recruiting women as suicide bombers was an effective tactic that Boko Haram most likely learned from terrorist groups abroad. “Women traditionally are not expected to be in the role of a suicide bomber in Nigeria,” he told Vice News. “They are less likely to be suspected, inspected or detected.”

Boko Haram launched its first female suicide attack in June. Meanwhile, the Islamic State group in the Middle East has recruited women into its ranks, as well. A wanted British woman known as the White Widow joined the militant group formerly known as either ISIL or ISIS last year: She was reportedly training an all-female brigade of suicide bombers for the group in September, according to the New York Post. The group has also established an all-female squad in the Syrian city of Raqqa that is charged with policing other women under the Islamic State’s interpretation of Shariah, or Islamic law.