RAMALLAH (Ma'an) -- Jailed hunger striker Samer Issawi has stopped drinking water after refusing food for 188 days, the Palestinian Prisoners Society said Tuesday.

A PPS lawyer visited Issawi in Israel's al-Ramle prison clinic and said the prisoner has stopped drinking water and taking vitamins, and is boycotting all medical tests.

A doctor has informed Issawi that his heart could stop at any time if he stops drinking, the lawyer said in a statement. Issawi is suffering cramps and numbness and his weight has dropped to 47 kgs, the lawyer added.

Issawi thanked his supporters inside Palestine and internationally for their solidarity.

The prisoners society called on all Palestinians to intensify their efforts to support hunger strikers.

On Monday, Palestinian Knesset member Ahmad Tibi visited Issawi and said his health condition was critical.

From a wheelchair, Issawi told Tibi he was determined to continue his strike.

"The only choices I have are to triumph or die a martyr. I feel I am closer to martyrdom, and the battle I am fighting isn't a personal one as I am seeking to protect national accomplishments achieved within the Shalit deal," he said.

Issawi was released in the Oct. 2011 prisoner swap agreement between Israel and Hamas, which secured the release of Israeli soldier Gilad Shalit from Gaza.

He was rearrested on July 7 and accused of violating the terms of his release by leaving Jerusalem. Israeli prosecutors are seeking to cancel his amnesty and detain him for 20 years, the remainder of his previous sentence.

Issawi told Tibi he is willing to be tried in a magistrates court and to serve a short sentence for entering areas "which are in the first place part of my homeland," but he will not agree to serve another 20 years in Israeli jails.