New Delhi, April 13 -- Security across the national capital was tightened on Monday after a workers' protest in neighbouring Noida escalated into violence, prompting Delhi Police to mount a high alert along key border entry points. Authorities moved swiftly to prevent any spillover into Delhi following clashes, vandalism and arson reported from industrial zones in Uttar Pradesh.

The unrest began in Noida's Phase 2 and Sector 60 areas, where a large gathering of factory workers from multiple industrial units assembled to press for long-standing demands related to salary revision. What began as a demonstration soon deteriorated, with reports of stone-pelting, damage to vehicles and property, and at least one car being set ablaze.

Official...