Any solution provided by Research in Motion, makers of BlackBerry smartphones, must pass through field trials to satisfy India's security concerns, a senior government source said on Friday.

We will only accept a solution which will enable us lawful interception of BlackBerry services in the interest of national security, the source told Reuters.

The solution, if they come up with it, will have to go through field trials and satisfy our technical experts, he added.

RIM faces an August 31 deadline to give authorities the means to track and read BlackBerry Enterprise email.

(Reporting by Bappa Majumdar; editing by Malini Menon)