British scientist Stephen Hawking has withdrawn from a high-profile Israeli conference in June, in support of an academic boycott of the country.
He initially planned to speak at the event, but pulled out following advice from Palestinian academics.
Pro-Palestinian campaigners said Professor Hawking, 71, wrote to the organisers on 3 May saying that he had planned to criticise the Israeli government.
His withdrawal follows representations by Palestinian academics and pro-Palestinian groups.
The BBC reports he has been criticised by conference organisers.
"The academic boycott against Israel is in our view outrageous and improper, certainly for someone for whom the spirit of liberty lies at the basis of his human and academic mission," conference chairman Israel Maimon said in a statement.
A spokesman for the Fair Play group, which campaigns against boycotts of Israel, described the scientist's withdrawal as "bizarre".
"Professor Hawking could have joined the conference and explained his views on the conflict in the region, just as many other participants have done.
"By boycotting the conference, he has thrown away this opportunity and will help nobody."