JERUSALEM (AFP) -- Israel has moved several of its Hamas prisoners to solitary confinement, media reported on Sunday three days after Prime Minister Benjamin Netanyahu vowed to make their conditions harsher.
Internet news site Ynet said that "at least seven senior Hamas operatives" had been transferred.
Netanyahu said on Thursday that as the Palestinian Islamist movement refused to allow Red Cross visits to Gilad Shalit, an Israeli soldier it has held for five years, he would cut privileges of Hamas militants in Israeli jails, such as external university courses.
"There will be no more master's degrees in murder or doctors of terrorism," he told an international seminar in Jerusalem. "This party is over."
Israeli public radio on Sunday said Hamas prisoners planned to hold a one-day hunger strike on Monday in protest.
A spokeswoman for the Israel Prisons Service refused to comment on the reports.
On Sunday, a day after Israel marked five years since Gaza-based militants seized his son in a cross-border raid, Shalit's father said that Netanyahu's failure to secure his release amounted to a death sentence.
Netanyahu "does not have a mandate to sentence Gilad to death," Noam Shalit said, speaking at a news conference at the protest tent in which the family lives outside Netanyahu's residence in Jerusalem.
"Netanyahu and his advisers, through some unexplainable weakness, are afraid to take a decision with risks, even though these are measured risks," he said, referring to a prisoner exchange.
Gilad Shalit was 19 when he was captured on June 25, 2006 by three armed groups, including Hamas, and he has been held ever since at a secret location in the Gaza Strip.
The last sign of life dates back to October 2009 when Hamas released a video of him calling on Netanyahu to do everything to free him.
In German-mediated negotiations with Hamas, Netanyahu has so far insisted that in order to meet the group's demand for the release of 1,000 Palestinians, including 450 with Israeli blood on their hands, some of the worst offenders must be exiled.
Netanyahu said Sunday that although he had agreed to what he called "harsh" terms he has had no response from Hamas.
"We received a proposal from the German mediator. This proposal was harsh, it was not simple," he said at Sunday's weekly cabinet meeting.
"However, we agreed to accept it... As of now, we have yet to receive Hamas's official answer to the German mediator's proposal."
Hamas flatly denied Netanyahu's account of events.
"Netanyahu is using a policy of lies and delays to cover up his failed role in the German mediation to reach a prisoner exchange agreement," Hamas spokesman Sami Abu Zuhri said in a statement.
In Berlin on Sunday, Chancellor Angela Merkel's spokesman Steffen Seibert said in a statement that she met Israeli opposition leader Tzipi Livni, and that both reiterated a call for Shalit to be freed immediately.
Several protests calling for Shalit's release were held over the weekend in Israel.
France's ambassador Christophe Bigot gave the Shalits a letter from French President Nicolas Sarkozy addressed to Gilad, who also holds French nationality, saying "France will never abandon you."