The Burning Man organization has written a letter to top federal officials threatening a federal lawsuit in the wake of continuing traffic stops slowing vehicles headed to the 80,000-person event, which begins midnight Sunday. 

The organization called for an immediate stop to the "improper and apparently unconstitutional behavior" and also demanded that all involved federal agencies preserve all records related to the traffic stops in a letter obtained by the Reno Gazette Journal. 

IF IT HAPPENS TO YOU: What to know if you get pulled over on way to Burning Man

The projected end of the law enforcement operation is Sept. 5, according to Pyramid Lake Police Department Lt. Michael Durham. Burning Man lasts for a week, through Sept. 3. 

"Many of the (traffic stop) tactics are attempts to intimidate and harass travelers who are doing nothing more than passing through the Reservation on a state-maintained highway. This is unacceptable and this behavior should not be tolerated by agency leaders nor the public," said Adam Belsky, special counsel to the Burning Man organization in the Wednesday letter.