Britain is to halve the amount of money it gives in humanitarian aid to Nigeria over the next few years, says the international development minister.

The aid worth £200m ($258m) over the next fours years is a 50% drop from the £100m it spent in the past 12 months.

The money is aimed at victims of attacks by Boko Haram Islamist militants in north-eastern Nigeria.

More than 1.5 million people are on the brink of famine in the area, aid agencies say.

International Development Minister Priti Patel said the Nigerian authorities needed to do more to defeat the extremists and to "secure the safety and well being of its own people".

She also said other donors should increase their assistance.

On being asked if she was comfortable with a substantial cut in Britain's humanitarian aid, Ms Patel replied that she did not see it as a cut because she had just announced more money for Nigeria.

"My job isn't just to give aid and money... but also to get others to contribute as well."