LOS ALAMOS, N.M. - Officials at Los Alamos National Laboratory say they have been ordered to increase security, but they won't say why.

In a press release Friday afternoon, the lab said that the National Nuclear Security Administration has directed it to increase security immediately, meaning vehicles and visitors will be subject to extra checks.

Lab spokesman Kevin Roark said lab officials never discuss the reasons behind security alerts. He did say the order was exclusive to Los Alamos, and not all of the nation's nuclear facilities.

He declined to say if the order had anything to do with a faulty $213 million security system that is being installed around the lab's most sensitive nuclear facilities.

The system was supposed to be up and running this summer. But officials now say it will take an additional $41 million and another six months.

Last month five security workers were fired for taking unauthorized visitors to a shooting range on the campus.

© Copyright 2013