ABUJA, Nigeria — Islamist insurgents have killed hundreds in a town in Nigeria’s northeast this week, the area’s senator, a resident and the Nigerian news media reported on Wednesday, as more than 200 schoolgirls abducted by the militants, known as Boko Haram, remained missing.

The latest attack, on Monday, followed a classic Boko Haram pattern: Dozens of militants wearing fatigues and wielding AK-47s and rocket-propelled grenade launchers descended on the town of Gamboru Ngala, chanting “Allahu akbar,” firing indiscriminately and torching houses. When it was over, at least 336 people had been killed and hundreds of houses and cars had been set on fire, said Waziri Hassan, who lives there, and Senator Ahmed Zanna.

The missing schoolgirls have grabbed the world’s attention, and more offers of help poured in to the Nigerian government on Wednesday from Britain, China and France. But Boko Haram’s deadly attack on Gamboru Ngala was similar to many others in the past several years that drew little or no notice beyond Nigeria. Bodies still lay in the street on Wednesday night, said Mr. Hassan, a cement salesman.

The town is on the Cameroon border and, as with other Boko Haram targets, many of its youth had joined an anti-Islamist vigilante force and were helping the Nigerian Army. “The young men have been defending the town for quite some time,” Mr. Zanna said. The insurgents have punished other such towns in the region with mass killings and indiscriminate arson.