Israel has arrested a World Vision employee after detaining him for more than a month and raiding World Vision offices in Gaza.

Israel’s internal security agency, the Shin Bet, says Mohammed el-Halabi siphoned off millions of the charity’s funds and transferred them to the Islamic militant group Hamas, assisting it in building tunnels and purchasing arms. World Vision is protesting the arrest.

Hamas is listed as a terrorist organization by the U.S. State Department. It is also part of the Palestinian government, having won elections a decade ago.

The Guardian reports that Shin Bet says Halabi admitted during interrogation to being a member of Hamas and that he was ordered to “infiltrate” World Vision, one of the world’s foremost evangelical aid organizations. The paper also reports that “Halabi is likely to have been denied access to a lawyer for long periods of his detention.”

Halabi was in an Israeli prison for 50 days before being charged. World Vision’s full statement on their website follows:

On June 15th, 2016, Mohammad El Halabi, the manager of operations for World Vision in Gaza, was arrested on his way home from routine meetings. On August 4th 2016, after 50 days in Israeli state detention, Mohammad was charged with providing support to Hamas. World Vision was shocked to learn of these charges against Mohammad.

World Vision is a Christian relief, development and advocacy organisation dedicated to working with children, families and communities to overcome poverty and injustice. World Vision serves all people regardless of religion, race, ethnicity or gender. World Vision has been working in Israel/Palestine for over 40 years, striving to give hope to over 500,000 of the most vulnerable children, through education, health, child protection and resilience programs. “We continue to call for a fair, legal process.”

World Vision subscribes to the humanitarian principles of impartiality and neutrality and therefore rejects any involvement in any political, military or terrorist activities and maintains its independence as a humanitarian aid agency committed to serving the poor, especially children. World Vision has detailed procedures and control mechanisms in place to ensure that the funds entrusted to us are spent in accordance with applicable legal requirements and in ways that do not fuel conflict but rather contribute to peace.

World Vision programs in Gaza have been subject to regular internal and independent audits, independent evaluations, and a broad range of internal controls aimed at ensuring that assets reach their intended beneficiaries and are used in compliance with applicable laws and donor requirements. Based on the information available to us at this time, we have no reason to believe that the allegations are true. We will carefully review any evidence presented to us and will take appropriate actions based on that evidence.

According to the Associated Press, an Israeli Foreign Ministry official said that World Vision Senior Vice President Kent Hill was holding meetings in Israel in respone to the accusations. The official spoke on condition of anonymity because the meetings were private.