RAMALLAH, West Bank — Forensic experts from Switzerland, France and Russia on Tuesday took 20 samples each from the remains of Palestinian leader Yasser Arafat after his grave in the presidential headquarters here was opened.

The experts will take the samples to their respective countries to carry out tests to determine if Arafat, who died on Nov. 11, 2004, at a military hospital in France, was killed by polonium, a poisonous radioactive material.

French hospital reports at the time said he died from a massive brain hemorrhage, but gave no details on what caused a related blood condition, giving rise to Palestinian suspicions he was killed by Israel. Arafat’s wife requested at the time that no autopsy be performed, and Israeli officials have labeled as ridiculous any allegations that they played a role in his death.

The process Tuesday took only hours. The grave, buried 12 feet underground, was opened early in the morning and Palestinian forensic technicians removed samples for the experts.

After the grave was again closed, Palestinian officials held a short ceremony in which they laid wreaths.

Members of the media were not allowed to witness the grave opening; the site was sealed from view by sheeting.

Tawfik Tirawi, head of the Palestinian committee investigating Arafat’s death, said that “everything was done legally and professionally.”

Abdullah al-Bashir, a Jordanian doctor who heads a Palestinian medical committee empowered to follow up on the circumstances of Arafat’s death, said results should be available in about three months.