Eleven million people are in urgent need of humanitarian aid in the Lake Chad region following nine years of Boko Haram violence, a dozen NGOs warned on Thursday. The groups issued a plea for emergency aid to help communities surrounding the lake, which lies across Chad, Nigeria, Niger and Cameroon, ahead of a major donor conference about the crisis in Berlin next week. "The insurgency as well as military operations across the four countries have displaced 2.4 million people and left 5 million people food insecure, while significantly reducing economic activity," said the statement signed by the NGOs, including Norwegian Refugee Council, Save the Children and Action Against Hunger."The humanitarian community scaled up the response significantly in 2017, but humanitarian needs remain massive and will continue well into 2018 and beyond."The United Nations estimates it needs $1.6 bn to offer life-saving aid for the region in coordination with humanitarian actors. Boko Haram took up arms in 2009 in pursuit of an Islamic state in northern Nigeria but its insurgency has since spread to neighbouring states bordering Lake Chad, with frequent suicide bomb attacks.The conflict has aggravated an already difficult humanitarian situation in one of the poorest regions of the world.The territory around the lake is difficult to access and the majority of the aid must be delivered by heavy armed convoys and staff transported by costly helicopters.A donor conference in Oslo last year ended with a pledge by 14 countries to give $672m to help the region, well below the $1.5bn sought.However, less than half has so far been paid, the NGOs added.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.