Doctors said they planned to hold Prime Minister Ariel Sharon in the hospital until at least Tuesday as he undergoes more testing for a stroke he suffered Sunday night. Sharon was rushed to hospital after suffering the stroke and briefly losing consciousness. A senior aide to Sharon said the prime minister's condition had improved overnight, and that there were no external signs of stroke. Sharon himself seemed to be in good humor. “Apparently I should have taken a few days off for vacation, but we're continuing to move ‘forward,’” he said, using the name of his new party, Kadima. Meanwhile, Palestinians took to the streets of Gaza City, firing into the air and celebrating the news of Sharon’s illness. Photo: The heavy guarded entrance to the trauma unit of the Hadassa-Hospital in Ein Karem Jerusalem.