Popular support for a hunger strike by hundreds of Palestinians imprisoned by Israel has been gaining momentum with West Bank marches, sit-ins and a social media campaign showing video clips of celebrities from across the Arab world drinking salty water in solidarity. The strike is one of the largest such protests in recent years, with potential fallout beyond the prisoners' demands for better conditions in Israel lockups. A large rally in support of the hunger strikers has been scheduled for Wednesday, the day Abbas is to meet President Donald Trump at the White House for the first time. In the half-century since Israel captured the West Bank, Gaza Strip and east Jerusalem, hundreds of thousands of Palestinians have been imprisoned at one time or another for fighting against Israeli rule, for acts ranging from stone-throwing and membership in groups outlawed by Israel to carrying out attacks that wounded or killed Israelis. Israel has branded those involved in violence as terrorists. Currently, about 6,500 Palestinians are being held in Israeli prisons, including several hundred without charges or trial, according to Palestinian figures. Barghouti was convicted of a role in attacks that killed five people during the second Palestinian uprising; he never put up a defense, refusing to recognize the jurisdiction of an Israeli court. Assaf Librati, a spokesman for the Israel Prison Service, said Monday that 870 prisoners are still on hunger strike, down from a peak of about 1,300 last week. Librati did not say why more than 400 prisoners had ended the fast. He said the hunger strikers are being held separately from other prisoners, and that several of them are being kept in isolation. Barghouti's supporters have said he was moved into isolation on the first day of the protest, but Librati would not comment on Barghouti's status. The spokesman said the hunger strikers are being monitored by medical staff. All their personal items, including books, were taken from them at the start of the protest, he said. Qadoura Fares, who heads an advocacy group for Palestinian prisoners, alleged that the Israeli authorities are trying to weaken the resolve of the hunger strikers by isolating Barghouti and negotiating separate deals for each prison. Fares said that Barghouti would continue with the strike "even if he was alone, until he achieves the goal." In support of the hunger strikers, a general strike last week shuttered shops and schools in the West Bank and east Jerusalem. A campaign called "water and salt," initiated by the Barghouti family, is spreading on social media and at sit-in tents across the West Bank. Participants drink salty water in a show of solidarity. Several celebrities in the Arab world have already taken part, including the host of "Arabs Got Talent," who drank the salt water at the opening of his popular Beirut-based TV show over the weekend. Others included a prominent Iraqi football player and a Lebanese artist. Palestinian analyst Ahmad Al-Azem said the hunger strike is helping mobilize younger Palestinians who have been largely apathetic in recent years because paths to statehood appear to be blocked. "This will be a very important step for a new generation to think how we can start again because politically, we are in a crisis," said Azem. "Nothing is working, negotiations are not working, the occupation is continuing." — AP