NAIROBI, Kenya — The first famine of the 21st century has been been declared in southern Somalia by the United Nations. The famine is a result of a combination of drought, conflict and high food prices claims tens of thousands of lives and puts hundreds of thousands more at risk of starvation.

The famine declaration was made Wednesday by the U.N.’s humanitarian coordinator for Somalia, Mark Bowden, who said new research showed the threshold for famine had been reached or exceeded in Somalia's Bakool and Lower Shabelle regions and that 3.7 million — half the population of Somalia — were at risk.

Bowden warned that the famine would spread, worsening an already dangerous situation in the Horn of Africa where the regional drought is affecting close to 11 million people.

“If we don’t act now, famine will spread to all eight regions of southern Somalia within two months, due to poor harvests and infectious disease outbreaks,” Bowden said. He added that there would be no respite before the end of the year when the next harvest is due, assuming October’s rains do not fail.

For famine to be declared there must be acute malnutrition rates among children of at least 30 percent and two deaths per 10,000 people per day. In some parts of southern Somalia these thresholds had been exceeded with half the population acutely malnourished and a death rate three times higher than the famine.

“These are truly shocking figures,” Bowden said announcing that the U.N. needs $300 million to address the famine in the next two months alone.

“The U.N. announcing famine in parts of Somalia, the first in the region in the 21st century, must be an urgent wake up call to the rest of the world,” said Alun McDonald, a spokesman for Oxfam who urged donors to step up to alleviate the regional crisis.

“The crisis has been building for several months but the response from international donors and regional governments has been mostly slow, inadequate and complacent, and the aid response is still $800 million short of what is needed,” he said.

U.S. Secretary of State Hillary Clinton announced that the United States would provide a further $28 million in aid to people in Somalia and to countries hosting the estimated 3,500 refugees leaving the country everyday, mostly for camps in Ethiopia and Kenya.

Bowden compared the famine to the one that hit Somalia in the early 1990s and which killed more than 200,000 people.

“We are finding comparable [malnutrition] rates now … to the ‘91/92 famine in Somalia. It looks the same, and is the worst in 20 years and the most acute situation facing the region in two decades,” Bowden said.

That crisis triggered U.S. engagement as the head of the U.N. peacekeeping mission to Somalia, which resulted in the infamous Black Hawk Down episode in which 18 U.S. Rangers were killed in a battle with clan militias in Mogadishu.

Somalia remains an embattled country, without a fully functioning government and in a vicious conflict between the internationally-back transitional government and the Al Qaeda-affiliated Al Shabaab.

(More GlobalPost in Somalia: Inside Somalia: Life in Hell)

Both the areas where famine has been declared are controlled by Al Shabaab, which banned Western aid agencies from its territories in late 2009. Al Shabaab lifted its ban earlier this month but the damage has already been done.

Al Shabaab’s control of the famine areas complicates access to the worst affected parts but Bowden insisted that while “humanitarian operations in Somalia are difficult … they are not impossible.” He said the U.N. was in “dialogue” with local Al Shabaab cells and hoped to secure safe access for the U.N.'s World Food Program (WFP) and other international aid agencies.

Al Shabaab is listed as a terrorist organization by the United States.

Under U.S. law, aid agencies supplying food or medicine that finds its way into the hands of Al Shabaab can be prosecuted for supporting a terrorist group, leading to a dramatic decrease in U.S. support for WFP in Somalia in recent years.

The targeting of Al Shabaab and Al Qaeda leaders in Somalia by U.S. missile strikes, assassinations and drone attacks also threatens the aid effort.

“[Attacks on al-Shabaab] increases the level of suspicion of humanitarian organizations and their motivations and could have an impact on access,” said Bowden. “In the past missile strikes have led to a major disruption of humanitarian efforts," he said. "It’s an area of concern.”