NEW YORK — Somalia is facing a humanitarian “catastrophe” as an escalating conflict restricts aid agencies’ efforts to provide food and medical supplies, Doctors Without Borders said.

“Every time we think it can’t get much worse, it does,” the Geneva-based charity’s executive director in America, Nicolas de Torrente, said in a conference call yesterday.

The Horn of Africa nation has been wracked by violence since the government ejected Islamic fighters from southern and central areas in January 2007. The United Nations estimates 1 million Somalis are displaced within the country as people flee fighting between the Islamists and government forces, which are supported by Ethiopian soldiers.

Almost 3,000 children are in programs to help combat malnutrition, the group’s deputy operations manager for Somalia, Greg Elder, said. Some 500 more children are admitted every week as a lack of rain led to a poor harvest this year. Inflation and global increases in food and fuel prices are worsening the situation.

Some Somali families, once they have exhausted all their resources and cut down to one meal every few days, “are in the very difficult situation of having to decide which members of their families are expendable,” he said.

More than 250,000 internally displaced people live in camps around Mogadishu after fleeing violence in the country’s capital.

“They are trapped in this corridor of misery,” Mr. Elder said.