At least 100 civilians were killed in a Nigerian military airstrike on a crowded market in northwest Zamfara state, Amnesty International said Tuesday, urging authorities to launch an immediate investigation.

The airstrike, which hit the remote Tumfa market in Zurmi district Sunday, was the ​second to kill scores of ​people at ⁠a crowded market in northern Nigeria in a month.

Dozens of injured people were being treated at hospitals in Zurmi and nearby Shinkafi, Amnesty said, adding that many of those killed were women and girls.

The Nigerian military did not immediately respond to requests for comment but has previously denied targeting civilians, saying airstrikes are intelligence-led and hit only terrorist targets.

Citing witnesses, Amnesty ⁠said ⁠military jets had been spotted hovering around the area at midday and returned about two hours later and struck the crowded market.

In April, around 200 civilians were killed in a similar airstrike on a weekly market in Jilli, in northeastern Nigeria. The military has opened a probe into that incident.

Residents say ⁠they are increasingly worried about civilian deaths from military raids and strikes in northern regions.

Nigeria's military has been battling banditry ​in the northwest and a 17-year Islamist insurgency in the ​northeast. The United States struck what it said were Islamist bases in northwestern Nigeria on Christmas ⁠Day ‌last ‌year, after President Donald Trump accused Nigeria ⁠of failing to protect Christians.

"This ‌pattern of human rights violation is increasingly becoming the norm, with ​villagers at the ⁠receiving end of atrocities by both armed ⁠groups, bandits and the military," Amnesty said.

It called the ⁠airstrikes unlawful and ​said they showed disregard for civilian life.