The Sahel state of Niger said on Thursday it had sent security reinforcements to part of its border struggling with an influx of displaced people and criminals from neighbouring Nigeria.The measures have been taken in the Maradi area on the southern-central part of the border, which abuts the northwestern Nigerian state of Zamfara."We are currently registering many refugees, whole families who are coming over," Maradi Governor Zakari Oumarou told state television."We are (also) facing a new situation, of kidnappings for ransom."The "refugees" were mainly coming from Zamfara, he said, but did not give numbers or say why they were fleeing to Niger."We are in the process of focussing on security on our border. We have deployed plenty of units on the border and we will continue to do so."Oumara added: "We are going to continue to receive refugees, but there are bad people among them. So we will have to filter them, and we are doing that."Local communities should "take extreme care... and be vigilant," he said.Northeastern Nigeria is in the grip of a jihadist insurgency that has also spread into Niger, but cross-border problems from Zamfara, in the northwest, have typically been rare.A Maradi resident told AFP that regions all along the border with Nigeria were now prone to cross-frontier crime, particular cattle theft by "armed Nigerian gangs."* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.