Actress Mia Farrow has offered to give up her freedom so that an ailing Darfur rebel leader can get safe passage out of a hospital, according to a letter the celebrity activist wrote to Sudan's president and posted Monday on her Web site.

Suleiman Jamous, a moderate who has been a key link between Darfur rebels and aid workers in the war-torn Sudanese region, needs to leave the country for further medical care, Farrow said in the letter to President Omar al-Bashir, dated Sunday.

Jamous, suffering from abdominal problems, has been at a U.N. hospital outside Darfur. The U.N. has said he is free to leave, but he fears arrest or government reprisals if he does.

"As you are undoubtedly aware, Mr. Jamous is in need of a medical procedure that cannot be carried out in Kadugli," wrote Farrow, who has traveled to Darfur as a UNICEF goodwill ambassador and signed her letter with that title.

"I am therefore offering to take Mr. Jamous's place, to exchange my freedom for his in the knowledge of his importance to the civilians of Darfur and in the conviction that he will apply his energies toward creating the just and lasting peace that the Sudanese people deserve and hope for," she wrote.

Attempts to reach Sudan's Foreign Ministry spokesman early Tuesday were not immediately successful.

On Thursday, the Sudanese government said it would consider a separate written plea by activists and celebrities, including Farrow and South African Archbishop Desmond Tutu, that it guarantee Jamous safe passage.

More than 200,000 people have died and 2.5 million been chased from their homes in Darfur since 2003 when tribes of ethnic African farmers rebelled against the Arab-dominated central government, accusing it of neglect and discrimination.

Jamous, in his mid-60s and a leader of one of Darfur's largest rebel groups, the Sudan Liberation Army, was seized last year and transferred for medical treatment to the U.N. facility. He has faced threats from rival rebel chiefs and some government forces.

Humanitarian workers considered Jamous the leader who could best guarantee the safety of aid convoys, which often come under attack in the region. Activists also say Jamous could help restart negotiations between rebel groups and the government after last year's peace deal largely failed to end the violence.

UNICEF spokeswoman Kate Donovan said Monday that the organization was "not aware that Mia Farrow had written the letter to the president of the Republic of Sudan under her UNICEF goodwill ambassador title, and we'd like to consult with her before we make a comment."