The newspaper said Sunday the June 1 raid on Forward Operating Base Salerno was concerted attack by the Haqqani insurgent network, which has ties to intelligence service in neighboring Pakistan.
Officials told the Post the raid included detonation of a truck bomb inside the compound, which left two Americans and five Afghan civilians dead and more than 100 U.S. troops with minor injuries. The blast flattened the base mess hall and PX and damaged civilian homes as far as 2 miles away.
"It was a very huge explosion," said Daoud Khan Makeen, head of the provincial council in Khost.
A total of 14 insurgents were killed in the skirmish, including many who were wearing suicide explosive vests.
Sunday's report was the first to acknowledge the truck bomb and details of the casualties. The Post said the original Pentagon statement was limited to news that an attack on Salerno had been repulsed.
U.S. officials denied they downplayed the attack, citing NATO policy to not discuss non-fatal wounds. Most of the 100 injured were classified as wounded even though they were primarily just checked out for signs of concussion.
The attack, however, irked U.S. officials who have long suspected Pakistan was tolerating the presence of Haqqini units using Pakistani territory as a launching pad for operations inside Afghanistan.