Some states shut down the internet and suspended train and bus services on Monday.
Protesters are demanding the rollback of the plan to hire soldiers on a fixed four-year term, saying it would shatter their dreams of a secure job.
They have taken to the streets, blocking roads and torching trains.
Several opposition political parties have given their support to the protests. But the government has refused to cancel the plan, though it has been trying to allay the fears of protesters.
Demonstrations against the plan began in the northern states of Uttar Pradesh and Bihar last week after Prime Minister Narendra Modi's government announced changes to how it would recruit soldiers for the armed forces.
But they have now spread to several other states, with thousands of young men attacking train coaches, burning tyres and clashing with security forces.
At least one person died, and several others were injured in the southern state of Telangana where protesters clashed with the police on Friday.
Ahead of the shutdown on Monday, several states announced precautionary restrictions - banning large gatherings, shutting schools and even suspending internet services in some districts. In the state of Jharkhand, school exams have been postponed. And in Bihar, authorities have cancelled 350 trains in the wake of violence.