New York - More than 20 million people are at risk from famine in Yemen, Somalia, South Sudan and the northeast of Nigeria, the United Nations warned on Wednesday.The Security Council officially declared for the first time that the threat was directly linked to the armed conflicts raging in the afflicted areas."The Security Council notes the devastating impact on civilians of ongoing armed conflict and violence," the 15-member UN body said.The declaration added that the council "also emphasizes with deep concern that ongoing conflicts and violence have devastating humanitarian consequences and hinder an effective humanitarian response in the short, medium and long term and are therefore a major cause of famine in the situations above."It called on all parties involved in the various conflicts to "respect and protect medical facilities and personnel and their means of transport and equipment."The declaration, based on a Swedish initiative and subject to tough negotiations, was the first time the UN has formally established a link between famine and conflict in the region."The Security Council underlines the obligations of all parties to armed conflict to respect and protect civilians," it said.It went on to issue a call for "all parties in Yemen, South Sudan, Somalia and northeast Nigeria to urgently take steps that would enable a more effective humanitarian response."The council also called on UN members to make good on their pledge of aid to help tackle the burgeoning threat of famine.According to the UN's humanitarian affairs and emergency relief coordinator, only $2.5bn have so far been paid up by donors to tackle the crisis, out of a total of $4.9bn urgently needed.