Amnesty International's Nigeria chapter said "at least 100 civilians" were killed in the attack on the market, reportedly controlled by criminal gangs, while a resident of a nearby village put the toll at 117.
The strike came the same day that another attack by the Nigerian air force targeting bandits killed 13 civilians, in central Niger state, the victims' families told AFP.
News of attacks from both the Nigerian military and the various armed groups it is fighting often takes days to emerge from far-flung, rural areas.
But as the smoke cleared Monday, it appeared that Sunday was particularly deadly, with bandits also killing dozens of civilians in their own attacks.
The Nigerian military denied its strikes killed civilians in both instances.
Bandit gangs, motivated by money rather than the political or religious ideals of Nigeria's jihadist groups, raid villages, conduct kidnappings for ransom, and force farmers and miners to pay "taxes" in rural areas with minimal state presence.
They are decentralised armed groups that have at times battled Nigeria's more centrally organised jihadist factions -- and also worked with them against common targets.
Known locally as "bandits", they emerged in the country's northwest, growing out of conflicts between farmers and herders that spiralled into organised armed groups seeking quick money in the impoverished countryside, sometimes numbering hundreds of men.
Armed gangs killed 30 travellers in an attack Sunday in Zamfara state, in a massacre unrelated to the air strike, according to a security report prepared for the UN and seen by AFP.
The same day, bandits launched "coordinated attacks" in Katsina state that killed 12, according to another UN security report.
Death toll disputed
The Nigerian military has killed hundreds of civilians in its air campaigns against both bandits and jihadists.
Amnesty International Nigeria condemned the strike in Tumfa village, in Zamfara state, which it said killed "at least 100 civilians".
Garba Ibrahim Mashema, a community leader in the area, put the number of dead lower, at 72, but said: "The actual death toll is hard to establish at the moment."
"Everybody, residents and bandits, goes to the market," he told AFP. "People are at the mercy of the bandits. There is nothing they can do."
"Many young girls selling millet porridge and tofu in the market were killed," said Aliyu Musa, a resident of Zurmi town, seven kilometres from Tumfa, who put the toll at 117.
"To be frank, Tumfa market is under the control of bandits. It is their stronghold, any person who goes there knows he is on their turf."
In a statement, the military said that it targeted "terrorist leaders and commanders from across the west African sub-region".
Queried by AFP, Defense Headquarters spokesman Major General Michael Onoja said the reports of civilian deaths in Zamfara were "not true".
Regarding the airstrike that local residents said killed 13 civilians in Niger state, the military also denied reports of innocent deaths, while also saying it would investigate.
Those strikes took place in Shiroro local government area, home to known hideouts for a Boko Haram jihadist faction, as well as non-ideological bandits.
"It was not intentional. I commiserate with the family of the victims," Shiroro local government council chairman Isyaku Bawa told AFP.
Local resident John Ezra, of Kusasu village, said the villagers were "not close to the hideout of the terrorists, but our homes were bombed."
In April, the Nigerian military bombed a crowded market in Jilli, on the border of northeastern Yobe and Borno states, killing at least 56 people, many of them civilians, in a strike it said was directed at jihadists.
The military said it would investigate.
No updates have been publicly released.
The Nigerian military has killed hundreds of civilians in its air campaigns against both bandits and jihadists.
Amnesty International Nigeria condemned the strike in Tumfa village, in Zamfara state, which it said killed "at least 100 civilians".
Garba Ibrahim Mashema, a community leader in the area, put the number of dead lower, at 72, but said: "The actual death toll is hard to establish at the moment."
"Everybody, residents and bandits, goes to the market," he told AFP. "People are at the mercy of the bandits. There is nothing they can do."
"Many young girls selling millet porridge and tofu in the market were killed," said Aliyu Musa, a resident of Zurmi town, seven kilometres from Tumfa, who put the toll at 117.
"To be frank, Tumfa market is under the control of bandits. It is their stronghold, any person who goes there knows he is on their turf."
In a statement, the military said that it targeted "terrorist leaders and commanders from across the west African sub-region".
Queried by AFP, Defense Headquarters spokesman Major General Michael Onoja said the reports of civilian deaths in Zamfara were "not true".
Regarding the airstrike that local residents said killed 13 civilians in Niger state, the military also denied reports of innocent deaths, while also saying it would investigate.
Those strikes took place in Shiroro local government area, home to known hideouts for a Boko Haram jihadist faction, as well as non-ideological bandits.
"It was not intentional. I commiserate with the family of the victims," Shiroro local government council chairman Isyaku Bawa told AFP.
Local resident John Ezra, of Kusasu village, said the villagers were "not close to the hideout of the terrorists, but our homes were bombed."
In April, the Nigerian military bombed a crowded market in Jilli, on the border of northeastern Yobe and Borno states, killing at least 56 people, many of them civilians, in a strike it said was directed at jihadists.
The military said it would investigate.
No updates have been publicly released.
