Officials told the Post that the whereabouts of Rep. Markwayne Mullin of Oklahoma are unknown.
The report said that Mullin, 44, became enraged on Monday when a U.S. ambassador refused his request to help move large amounts of money into Tajikistan for his mission to save an American mother and her four children. The ambassador told him the request would be illegal, which reportedly prompted Mullin to threaten the ambassador and his staff.
The Republican had ignored warnings from the State Department and the Pentagon to avoid travelling to Afghanistan.
Mullin had said he was planning to hire a helicopter to help the 5 Americans escape the Taliban-controlled country. He was flying from Tblisi, Georgia, into the capital of Tajikistan, Dushanbe.
"To say this is extremely dangerous is a massive understatement," said one unidentified official to the Post.
The Pentagon had previously denied Mullin's request to travel to Afghanistan from Greece last week.
On Tuesday, President Joe Biden pledged support for those Americans even as the administration was lambasted by critics for previously saying no Americans would be stranded.
"The bottom line, 90% of Americans in Afghanistan who wanted to leave were able to leave. And for those remaining Americans, there is no deadline! We remain committed to get them out if they want to come out!" shouted Biden during his address to the nation.
Here's more about the Americans abandoned in Afghanistan:
Biden Pledges Support To Americans Still In Afghanistan www.youtube.com