London (CNN) The British government says it will not publish a classified report into the funding of Islamist extremism out of concerns for national security.

Home Secretary Amber Rudd summarized some of the review's findings in a ministerial statement released to parliament Wednesday, but said the government would not release the full report.

"Having taken advice, I have decided against publishing the classified report produced during the review in full," Rudd said in the statement.

"This is because of the volume of personal information it contains and for national security reasons."

Rudd said the report found that the most common source of funding for Islamist extremist groups in the United Kingdom is from "small, anonymous public donations coming from UK-based individuals."

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