The U.S. Supreme Court has put a crimp in the FBI's surveillance efforts thanks to its recent landmark ruling on GPS tracking, agency director Robert Mueller said Wednesday.

Testifying before Congress, Mueller said the ruling on installing tracking devices on a suspect's vehicle required the FBI to kill a number of GPS units already in use.

It will inhibit our ability to use this in a number of surveillances where it has been tremendously beneficial, Mueller said of the Supreme Court's ruling in U.S. v. Jones.

In that case, the Supreme Court ruled that law enforcement officials violated Washington, D.C., nightclub owner Antoine Jones' constitutional right against unreasonable searches when they trespassed on his property by installing a GPS device on his vehicle without a warrant.

While the majority of the court sidestepped the larger issue of whether the month-long surveillance of Jones' car violated his reasonable expectation of privacy, the ruling has been a hurdle for the FBI's suspect-tracking efforts.

Putting a physical surveillance team out with six, eight, 12 persons is tremendously time intensive, said Mueller, according to The Associated Press, adding that GPS allows surveillance teams to focus on other suspects.

The ruling caused a sea change, FBI General Counsel Andrew Weissmann said in a Feb. 24 speech. He said the FBI had to turn off about 3,000 GPS devices in use and had asked courts to let them briefly activate some units so they can be retrieved, according to The Wall Street Journal. The Journal reported that Weissmann said the FBI will draft new guidelines for using GPS devices.