ZURICH (AP) — FIFA President Sepp Blatter has called on Israeli soccer officials to “urgently” help a Palestinian player on hunger strike in Israeli custody.

Blatter wrote to the Israel Football Association of his “grave concern” after receiving reports that “several Palestine football players have allegedly been illegally detained.”

Blatter asked IFA President Avi Luzon to intervene with Israeli authorities with “utmost urgency” because of the “alarming situation” facing Mahmoud Sarsak.

Sarsak, 25, is reported to have been on hunger strike for almost three months, and has lost about 30 kilograms, according to global players’ union FIFPro.

On Monday, Sarsak reportedly eased his fast, agreeing to drink milk for 72 hours, according to a prisoners rights group. Israeli officials said Sarsak was no longer fasting.

Palestinian officials and FIFPro say Sarsak has been held without trial since 2009. They say he was stopped at a Gaza Strip checkpoint while traveling to an international match.

Israeli authorities claim Sarsak was involved in militant activity, including the training and recruiting of militants and producing explosives.

Palestinian prisoners ended a mass hunger strike last month, but Sarsak held out.

Before being detained, Sarsak played for the Palestinian national team.