Three policemen were shot dead by suspected al-Qaeda members in a village near the border with Burkina Faso.
One soldier was killed and two others wounded when a military convoy was attacked close to Nigeria's border.
Thursday's attacks came three days before Sunday's controversial presidential run-off election.
The opposition has said they will not recognise the results of the vote, and their candidate Hama Amadou, is currently receiving medical treatment in Paris after spending months in jail.
Niger's Interior Minister Hassimi Massaoudou says the attack in a market in Dolbel village close to Burkina Faso was the work of al-Qaeda in the Islamic Magrib (AQIM), which has been active in the region.
"The attackers were repelled, and we are currently sweeping the area," he told the AFP news agency.
The other attack was carried out by four suicide bombers in southern Diffa region that has often been targeted by Nigeria's Boko Haram insurgents.
A fifth suicide bomber, a young girl, was prevented from detonating her vest, Mr Massaoudou added.
Niger has porous borders with Libya, Algeria, Mali and Burkina Faso, which have all been hit by AQIM recently, and Nigeria to the south - making it vulnerable to Islamist attacks.
The country is rated by the UN as one of the world's least-developed nations and was recently named as the worst country to live in.

Last year meldonium was added to the World Anti-Doping Agency prohibited substance list and several athletes later tested positive for the drug.
Tennis player Maria Sharapova is now serving a two-year ban.
"Athletes and their entourage have ample time to familiarise themselves with the list," Wada president Craig Reedie said.
"There can be no tolerance for people who intentionally break the rules."
The updated list comes into force on 1 January 2017.
It covers substances and methods banned in and out of competition, and which substances are banned in different sports.
Wada said in April that scientists were unsure how long meldonium stayed in an athlete's system.
It also suggested athletes who tested positive before 1 March could avoid bans, provided they had stopped taking it before 1 January.
Sharapova, 29, tested positive for meldonium at the Australian Open in January 2016 and an out-of-competition test on 2 February.
The Russian said she had been taking meldonium since 2006 for health reasons and was unaware it had been added to the banned list as she knew it only by the name mildronate.
Islamist militants from al-Qaeda and Boko Haram have killed four security forces in two separate attacks in Niger, officials have said.
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Athletes have been warned to prepapre for an updated list of banned substances coming into force in 2017.