Niger has warned that the presence of thousands of Nigerian refugees will exacerbate an already existing food crisis in the country.

The prime minister said that a cereal deficit due to uneven and insufficient rainfall will make the country unable to feed its people and refugees who have fled due to Nigerian terror group Boko Haram's insurgency, Reuters reported.

Who are Boko Haram?

Boko Haram fights against Western influence in Nigeria and aims to impose its version of Sharia law in the country. The group declared an Islamic caliphate in Gwoza, along the Cameroon border, in August 2014.

Boko Haram has raided several cities in the north of the country in a bid to take control of more land.

Three states, Adamawa, Borno and Yobe, have been under a state of emergency since May 2013, due to Boko Haram's deadly attacks.

"The state does not have enough resources to handle this situation and that's why we need help," Prime Minister Brigi Rafini said during a meeting with financial partners.

The UN's Office for the Coordination of Humanitarian Affairs (OCHA) estimated that some 3.4 million people could face food insecurity in the country.

Niger, together with Chad, Benin and Cameroon, has deployed troops to Nigeria to help the local army in the fight against Boko Haram, which has killed thousands of people in north-eastern Nigeria in recent years.

Since the deployment of African Union (AU) troops in February, the Nigerian military has regained control of several areas held by the terrorists, whose insurgence started in 2009.

The deployment followed President Goodluck Jonathan's decision to postpone presidential elections by six weeks on the grounds of security.

In February, Nigeria announced the fight against the insurgents, who recently pledged allegiance to terror group Islamic State (Isis), was almost over. However, critics have cast doubts on previous claims by the Nigerian government and army that they had reached a truce with the terrorists.