NIAMEY (Reuters) - Niger has arrested five people near the Nigerian border suspected of belonging to the militant Nigerian Islamist group Boko Haram, Niger security officials said on Tuesday.

The group has been blamed for more than 1,000 deaths in Nigeria since 2010. Observers say they suspect it is using Niger as a transit route to link up with other militant groups like Al-Qaeda in the Islamic Magreb, now controlling northern Mali.

"State Security Police arrested the five suspected Boko Haram members who entered Niger on Sunday through the Zinder region. They have been transferred to Niamey for further questioning," a security official said, asking not to be named.

Another security official said Niger had heightened security along its border with Nigeria as the country intensifies its fight against the militant group, which wants to carve out an Islamic state in northern Nigeria.

Nigeria's military said on Monday it had killed 35 members of Boko Haram and arrested several during an overnight gunbattle in Damaturu, capital of northeastern Yobe state which borders Niger. (Reporting by Abdoulaye Massalatchi; Writing by Bate Felix; Editing by Andrew Roche)