Around 49 died and 17 were injured in the village of Tchombangou, while another 30 died in Zaroumdareye - both near Niger's western border with Mali, Reuters reports.
There have been several recent violent incidents in Africa's Sahel region, carried out by militant groups.
France said on Saturday that two of its soldiers were killed in Mali.
Hours earlier, a group with links to al-Qaeda said it was behind the killing of three French troops in a separate attack in Mali on Monday.
France has been leading a coalition of West African and European allies against Islamist militants in the Sahel.
But the region continues to be affected by ethnic violence, banditry, and human and drug trafficking.
In light of Saturday's attacks, Interior Minister Alkache Alhada said soldiers had been sent to the area, according to French outlet RFI. But Mr Alhada did not say how many casualties there had been across the two villages.
A local official, quoted by AFP news agency, said many people were killed, and a local journalist spoke of up to 50 deaths.
Niger's Tillabéri region, where the villages are situated, lies within the so-called tri-border area between Niger, Mali and Burkina Faso, which has been plagued by jihadi attacks in recent years.
Travel by motorbike has been banned in the region for a year, as part of efforts to stop incursions by Islamic militants, who often launch attacks from the vehicles.
Areas of Niger are also facing repeated attacks by jihadists from Nigeria, where the government is fighting an insurgency by Boko Haram.
Last month, members of the group killed at least 27 people in Niger's south-eastern Diffa region.
The latest attacks in Tillabéri come amid national elections in Niger, as President Mahamadou Issoufou steps down after two five-year terms.
Last Octobert an American hostage kidnapped in Niger was freed in a raid by US special forces.
Philip Walton was abducted on Monday from a village close to the border with Nigeria.
He was taken across the border into Nigeria and rescued on Saturday.
Jihadist and criminal groups are known to operate in the area. It's thought at least six hostages are currently being held captive in the Sahel area.
Mr Walton was abducted from the village of Massalata, where he had been living with his wife and child for two years, his father told AFP news agency.
Locals said six men armed with AK47s arrived in the village on motorbikes.
It's unclear why Mr Walton was targeted and who the armed group were.
In August, six French aid workers as well as their driver and local guide were killed by gunmen in the Koure area of Tillebery region, which attracts tourists who want to see the last herds of giraffe in West Africa.
At least six Western hostages are being held in Niger, Mali and Burkina Faso, including the American aid worker Jeffery Woodke, who was kidnapped in central Niger four years ago.
Election officials announced provisional results on Saturday, showing a lead for Mohamed Bazoum - a former minister and a member of Niger's ruling party.
A second round of votes is expected to be held on 21 February, once ballots have been validated by the country's constitutional court.
Attacks on army positions and civilians across the region are occurring with increasing regularity, despite the presence of thousands of troops from both the countries affected and France.
Recently 89 soldiers from Niger were killed in the latest attack to see dozens of deaths among regional armed forces. France has also suffered significant casualties, losing 13 soldiers in a helicopter crash in Mali in November.
The Sahel region, a semi-arid stretch of land just south of the Sahara Desert, has been a frontline in the war against Islamist militancy for almost a decade.
However, it is increasingly clear that the problem facing Chad, Niger, Mali, Burkina Faso and Mauritania (known as the G5 Sahel) is not just the presence of armed groups, and that more than military action is urgently needed to address a worsening humanitarian crisis, climate change and development challenges.
The overarching worry is that the crisis could spread further across West Africa.
The security crisis in the region started in 2012 when an alliance of separatist and Islamist militants took over northern Mali, triggering a French military intervention to oust them as they advanced towards the capital, Bamako.
A peace deal was signed in 2015 but was never completely implemented and new armed groups have since emerged and expanded to central Mali, Burkina Faso and Niger.
Casualties from attacks in those countries are believed to have increased fivefold since 2016, with over 4,000 deaths reported last year alone.
A stretch of land covering the border areas of Burkina Faso, Mali and Niger is at the centre of the insurgency and counter-terrorism operations.
Armed groups, including some linked to al-Qaeda and others the Islamic State group, have expanding their presence and capabilities.
The reasons behind their expansion are multiple:
- Porous borders and little state presence in some areas
- They have set up lucrative money-raising activities, such as imposing taxes, and trafficking drugs, weapons and people, which help fund their activities
- Soldiers fighting the militants appear to be under-trained and poorly equipped, despite the regional and international support they receive
In addition to the joint G5 Sahel countries, which have an estimated 5,000-strong force battling the militants, the French have had 4,500 soldiers deployed in the Sahel since 2013.
The UN also has over 12,000 peacekeepers in Mali, while the US has two drone bases in Niger, providing intelligence and training support throughout the region.
Amid the rising insecurity, so-called self-defence groups have been formed. In Mali and Burkina Faso, these militias are believed to be behind a number of massacres.
Ethnic tensions and economic rivalries have become mixed up with the Islamist insurgency, with accusations that members of the mainly Muslim Fulani ethnic group are linked to Islamists, which their representatives deny.
In addition, expanding deserts and climate change have magnified long-standing conflicts between mainly Fulani herders and pastoralists.
All this has led to the creation of ethnic militias on both sides, which have also been responsible for a horrific cycle of tit-for-tat mass killings.
Some security forces have been accused by human rights groups of unlawful killings during counter-terrorism operations.
Last week, a coalition of NGOs said that the "military response in the Sahel is part of the problem".
Action Against Hunger, the Norwegian Refugee Council and Oxfam estimated that the army operation in Mali had forced more than 80,000 people to flee their homes - about 40% of all those displaced in the country.
As the population in the region is set to double over the next 20 years, the violence is exacerbating development challenges.
Growing enough food for everyone will become increasingly difficult and this is not being helped by the numbers of people who have been forced to flee their homes.
In Burkina Faso, the number of people internally displaced has risen from 40,000 at the end of 2018 to more than 500,000 at the end of 2019 - that is more that 2% of the population. In Mali, the number has practically doubled.
The violence is also storing up problems for future generations as some of the Islamist groups deliberately target schools and teachers, leaving hundreds of thousands of children without access to education.
They then become even more vulnerable to sexual exploitation, forced labour or recruitment into armed groups.
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