The U.N. Security Council for the first time on Wednesday linked conflict to the threat of famine facing more than 20 million people in Yemen, Somalia, South Sudan and northeast Nigeria.

The council said in a presidential statement approved by all 15 members that it deplored that some unnamed parties have blocked vital food and humanitarian aid to people in the four countries.

Council members stressed that conflicts and violence "have devastating humanitarian consequences ... and are therefore a major cause of famine" in the four countries.

Yemen, the Arab world's poorest nation, has been engulfed in civil war since 2014. In Somalia, the weak government faces attacks by al-Shabab extremists linked to al Qaida. South Sudan, the world's newest nation, plunged into ethnic violence in December 2013 and a 2015 peace agreement has not stopped the fighting. Northeastern Nigeria has faced a seven-year uprising by the Islamic State-linked extremist group Boko Haram.

The Security Council commended donors for providing humanitarian assistance in response to the four crises but said additional resources and funding are needed "to pull people back from the brink of famine."

According to the U.N., only $2.5 billion of the $4.9 billion needed has been received. As of Aug. 4, the largest contributions and commitments had been made by the United States, United Kingdom, European Union, Germany and Saudi Arabia.

The council asked Secretary-General Antonio Guterres "in light of the unprecedented threat of famine" to brief members in October on "impediments" in each of the four countries to responding effectively. It also asks him to make specific recommendations on how to address the impediments.

Sweden's deputy ambassador, Carl Skau, said his country took the initiative and drafted the statement "because we think more needs to be done to save the lives, to stop the risk of 20 million people dying, including many children."

Sweden in a note on the adoption called it "the largest humanitarian crisis since the creation of the United Nations" in 1945.

British Ambassador Matthew Rycroft called the council's statement very important because it "for the first time links the four famines to conflict."

"Famines are caused now, not just by the weather, not just by overcrowding, but by man-made factors and particularly man-made conflicts," Rycroft said. "It's important that this is on the Security Council's agenda."

U.S. Ambassador Nikki Haley said the threat of famine in the four countries is "the largest food security emergency since World War II."

Haley said the Security Council must continue to demand access for food and other life-saving supplies and services "and we must hold governments and armed groups blocking access accountable."