VILLACOUBLAY, France - A French military jet carrying an ailing Yasser Arafat landed today at an airfield outside Paris, bringing the Palestinian leader for treatment of a mysterious illness.

The 75-year-old Arafat - whose health crisis forced him to leave his headquarters compound in the West Bank city of Ramallah for the first time in nearly three years - was to be rushed by ambulance to the Hopital d'Instruction des Armees de Percy, southwest of Paris.

The facility is a military facility with a major trauma center that also specializes in the treatment of blood disorders, said Christian Estripeau, head of communications for military health services.

Arafat has been sick for the past two weeks and blood tests have revealed he has a low platelet count - a possible sympton of leukemia or other cancers or a number of other maladies. Doctors said they need to run more tests to find the cause.

Arafat's personal physician, Dr. Ashraf Kurdi, ruled out leukemia on Thursday. However, an Arafat confidant, Dr. Ahmed Tibi, said Friday that "at this point, no possibility has been eliminated." Tibi, an Israeli Arab legislator, said Israeli intelligence officials have speculated that Arafat might be suffering from leukemia and he indicated that Arafat might have some symptoms of the disease.

Platelets are blood components that aid in clotting. A low count can be caused by many medical problems, including bleeding ulcers, colitis, blood cancers such as leukemia and lymphoma, liver disease, lupus and chickenpox. The platelet count also can be low because of treatment with blood thinners.

Outside the Percy hospital - set on a hilltop with sweeping views of Paris - a small group of Arafat supporters gathered, holding bouquets of flowers and waving Palestinian flags.

"I am waiting for Yasser Arafat to tell him that we are with him," said Fatima Mera, a 35-year-old French woman of Moroccan origin. "We hope he will leave here and continue the struggle for the Palestinian people."

Hours earlier, Arafat had a somber departure from his sandbagged Ramallah headquarters, seen off by a few hundred loyalists gathered on a rain-slicked tarmac - in marked contrast to his triumphant arrival in the Palestinian lands a decade ago, when he held out the promise of statehood.

At daybreak today, Arafat, wearing a gray fur hat and an olive-colored jacket, was helped into a Jordanian military helicopter outside his headquarters.

He looked pale and jaundiced, but tried to smile as loyalists whistled and chanted, "With our spirit and our blood, we will redeem you, Abu Ammar," using his nom de guerre. He was accompanied by his wife, Suha, 42, who had rushed to his side from exile in Paris.

"I will be back soon, God willing. I'll see you soon," Arafat told aides during a stopover at a Jordanian military base, according to Ata Kheiry, deputy chief of the Palestinian mission in Jordan.