NIAMEY (Reuters) - Three gendarmes were killed in one of two attacks against security and defence forces near Niger's borders with Nigeria, Burkina Faso and Mali, the ministry of defence said in a statement on public television on Thursday.
The attacks highlight the difficulties surrounding border security in West Africa, which has suffered several high-profile extremist attacks in the past five months.
Niger has also been targeted numerous times by Nigeria-based Islamist group Boko Haram, which has launched cross-border attacks in its effort to carve out an emirate in Nigeria's northeastern region.
One attack took place late on Wednesday in the region bordering Burkina Faso and Mali, launched by assailants who arrived on four motorcycles and a Toyota pick-up.
"The ... attack led by armed unidentified individuals took place around 11:10 p.m. (2210 GMT) against a unit of the national gendarmerie who had come to secure the Dolbel market," said Colonel Ledru Moustapha in the televised statement.
Security forces were searching for the armed men.
Three members of Niger's defence forces were injured and five suicide bombers killed in a separate attack earlier on Wednesday blamed on Boko Haram in the region of Diffa. About five other militants fled the scene.
Niger's interior minister Hassoumi Massaoudou ordered the land borders to be closed on Sunday, the day of the second round of the country's presidential elections, which the opposition has said it will boycott.