Tension ran high in Tinkune after the royalists tried to cross the prohibited area.
Security personnel fired tear gas canisters to disperse the protesters and to take the situation under control.
Police have barred the entry of pro-monarchy supporters from Tinkune Bridge to Baneshwor.
The Rastriya Prajatantra Party, which has been advocating for the reinstatement of monarchy, has staged a demonstration today. Durga Prasain is leading the protest.