The White House declassified a four-page report on Friday afternoon, detailing Syrian President Bashar al-Assad's usage of chemical weapons in an Aug. 21 attack against rebel fighters. The documents were released as Secretary of State John Kerry addressed the nation on the ongoing conflict in Syria.

According to the report, at least 1,429 people — 426 of whom were children — were killed in last week's attack outside Damascus. Citing information from a “senior official intimately familiar with the offensive,” the document also claims that Assad's regime had planned the attacks, a point that Kerry emphasized during his statement.

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Kerry also said on Friday that the United Nations — currently on the ground in Syria to investigate the chemical weapons usage — "can't tell us anything that we haven't shared with you this afternoon, or anything we don't already know."

The White House also released this map to accompany the documents:

Read the report in full below:

U.S. Government Assessment of the Syrian Government’s Use of Chemical Weapons on August 21, 2013

Image: Ammar al-Arbini/AFP/Getty Images