A government-backed bill is slated to go before the Diet next month, potentially revising the definition of who can be arrested for conspiring to commit acts of terrorism as security concerns mount ahead of the 2020 Tokyo Olympics, government sources revealed Friday.

While a similar bill has been submitted to the Diet three times in the past only to be rejected due to public fears over the sweeping powers it could grant police, the new legislation would narrow the targets of authorities to "organized crime groups" — including terrorist groups — the sources said.

Earlier versions of the bill had not specified the law's targets, instead referring merely to "groups," something that had stoked fears that the law could be used to quell dissent.