JUBA, South Sudan (CNN) -- South Sudan's president has written to more than 75 government officials and eight foreign governments in an attempt to recover $4 billion lost to corruption.

"If funds are returned, the government of the Republic of South Sudan will grant amnesty and keep your name confidential," President Salva Kiir said in the letter, which was dated May 3 and sent to former and current "senior" officials.

Kiir said the government has set up a special bank account in Kenya where officials and "corrupt individuals with close ties to government officials" can deposit public funds. Those who refuse to return all or part of the stolen cash will be held accountable, he said.

"Most of these funds have been taken out of the country and deposited in foreign accounts," the letter said.

Kiir said he received "some positive responses" to letters he sent to eight heads of states, including the United States as well as countries in Africa, the Middle East and Europe.

The appeal comes as South Sudan's government struggles to make up for losing 98 percent of its revenue when it halted oil production amid a dispute over transportation and processing fees with Sudan. South Sudan acquired three quarters if the formerly united country's oil reserves when it became independent last July. But the countries have been unable to agree on how much the landlocked South should pay to use infrastructure that remains in Sudan.

South Sudan shut down production in late January after accusing Sudan of stealing $815 million worth of its oil. Sudan said it confiscated the crude to make up for unpaid fees.

The shutdown has sent the economies of both countries reeling, but South Sudan has been hit particularly hard by the loss of income from virtually its only export. The black market value of the South Sudanese pound fell from about 3.5 to the dollar in January to about 5 currently. Inflation has jumped almost 80 percent from May 2011 to May 2012, according to the National Bureau of Statistics.

In World Bank documents leaked to media last month, the Washington-based lender warned of "state collapse" if the country runs out of foreign exchange reserves, which it said could be depleted by July -- one year after South Sudan became the world's newest nation, following a two-decade civil war.

"We fought for freedom, justice, and equality. Many of our friends died to achieve these objectives," Kiir wrote in his letter. "Yet, once we got to power, we forgot what we fought for and began to enrich ourselves at the expense of our people."

When it declared independence, South Sudan became one of the world's poorest countries. Only 27 percent of the adult population can read and write, while just over half have access to clean water, according to the Statistics Bureau.

"There is still time to take critical decisions of saving our country from the crisis we currently face and to help the millions who are in desperate need of assistance in health care and education," Kiir said.

The Anti-Corruption Commission has recovered about $60 million in stolen public funds, according to a June 1 statement released by the office of the president.