RAMALLAH, Palestinian Territories — Israel poisoned the late Yasser Arafat with the lethal radioactive substance polonium, a nephew of the veteran Palestinian leader alleged on Thursday, prompting an Israeli denial.

"We accuse Israel of killing Yasser Arafat by poisoning him with that lethal substance," Nasser al-Qidwa told AFP, referring to polonium, traces of which were recently found on clothing worn by Arafat when he was ailing.

"Those responsible for that assassination should be held accountable and judged," said Qidwa, who is also president of the Yasser Arafat Foundation.

Allegations that the long-time Palestinian leader and Nobel Peace Prize laureate was poisoned were resurrected earlier this month after Al-Jazeera news channel broadcast an investigation in which experts said they had found high levels of polonium on his personal effects....