WATAMU, Kenya - South Sudan's president said Tuesday his government will ensure "unimpeded access" for all aid organizations, a day after famine was declared for more than 100,000 people in the country suffering from years of civil war.

The United Nations and others have long accused the government of blocking or restricting aid delivery in the East African nation.

President Salva Kiir's remarks to the transitional national assembly came after the famine was declared in parts of oil-rich Unity state. More than 100,000 people are affected, according to South Sudan's government and UN agencies. They say another 1 million people are on the brink of starvation.

South Sudan has repeatedly promised to allow full humanitarian access across the country, but with little effect. Some in Kiir's government have expressed hostility toward the international community, accusing it of meddling in the country's affairs.

Human Rights Watch researcher Jonathan Pedneault wrote Tuesday that the famine is a man-made result of "conflict, warring parties blocking access for aid workers and large-scale human rights violations."

The U.S. State Department said it was gravely concerned by the declaration of famine, calling the crisis "the direct consequence of a conflict prolonged by South Sudanese leaders who are unwilling to put aside political ambitions for the good of their people."

"We call on President Kiir to expeditiously make good on his promise that humanitarian and developmental organizations will have unimpeded access to populations in need across the country," acting State Department spokesman Mark Toner said in a statment.

Also Tuesday, the European Commission announced an 82 million euro ($87 million) emergency aid package for South Sudan, saying this is the first famine declared in the country since it gained independence from Sudan in 2011.

"The humanitarian tragedy in South Sudan is entirely man-made," EU Humanitarian Aid and Crisis Management Commissioner Christos Stylianides said in a statement.

Tens of thousands have died in the civil war that began in December 2013 and has continued despite a peace agreement in 2015. More than 1.5 million people have fled the country.

South Sudan also is experiencing severe inflation, which has made food unaffordable for many families.