Egyptian security officials on Monday said they arrested a former sergeant in the Israel Defense Forces after he illegally entered the Egyptian Sinai Peninsula from Israel.

The authorities say the unarmed 24-year-old, whom they identified as Andre Yaacoub, entered Egypt near the Taba crossing. He was detained by Egyptian authorities Monday. The officials, who spoke on condition of anonymity, say the Israeli was trying to reach the Gaza Strip through Sinai to fight alongside Palestinians.

Yaacoub, also known as Andre Pshenichnikov, a Jewish immigrant to Israel from Tajikistan, made headlines earlier this year when he announced he wanted to renounce his Israeli citizenship and move to a Palestinian refugee camp in the West Bank.

The Egyptian state-run Middle East News Agency reported that Pshenichnikov was not carrying a passport, and that his name had not been on tourist arrival lists. Israeli media reported that Pshenichnikov, a known pro-Palestinian activist, had crossed into Egypt with the intention of entering the Gaza Strip, an area that is off-limits to Israelis for security reasons.

Pshenichnikov said he wanted to cross the border "to join the Palestinian freedom fighters in Gaza and the Sinai Peninsula, the fighters against the Zionist occupation."

His mother, Svetlana, told Israel Radio that her son was in custody in Egypt and that he had intended to travel via Sinai to Cairo to rendezvous with friends from France.

"He received his visa [to visit Egypt] and went to Eilat, intending to cross into Egypt, tour the area and then go to Cairo, but Israeli police stopped him at the border and said he had tried to cross the border illegally,” Svetlana Pshenichnikov said in poor Hebrew with a heavy Russian accent. “They held him for several days and they demanded he sign an undertaking not to go to Cairo, but he refused. ... I promised I would do everything I could to help him."

She said Israeli authorities released her son after confiscating his Israeli and foreign passports, but that later in the day he had called from Taba and said he had been detained there by Egyptian authorities.

"After he finished his army service ... he supported [Palestinians]. ... He later rented an apartment in a refugee camp in Bethlehem to prove to the locals that there are Israelis who are in favor of peace," Svetlana said.

Egyptian security sources in Sinai said the detainee had been gathering information about Sinai from drivers in the area near the Taba border crossing between Egypt and Israel.

Egypt is trying to reassert control over Sinai, which has become a haven for terrorist groups since the uprising that overthrew Hosni Mubarak in February 2011.