Federal agents raided four metro Atlanta smoking shops Tuesday, executing search warrants that sought evidence related to synthetic marijuana and "bath salts," authorities said.

The U.S. Attorney's Office said in a statement that no arrests were made during the raids, which were carried out at Smoke 911 shops in Acworth, Roswell, Sandy Springs and Woodstock.

According to the U.S. Attorney's Office, five types of synthetic marijuana are currently designated as controlled substances under federal law.

The "bath salts," which are typically sold in powder and pill form, have effects that have been described as similar to those caused by other stimulants such at methamphetamine, Ecstasy and cocaine, the U.S. Attorney's Office said in the statement released Tuesday afternoon.

Authorities have not said what items were seized during Tuesday's raids.