Prime Minister Sher Bahadur Deuba has underlined the need of holding three-tier of elections for the implementation of constitution.During a press conference organised by Nepal Press Union in Kanchanpur on Saturday morning, PM Deuba said that the process of implementing the constitution will be moved ahead once the local, provincial and federal elections are held.He added that discussions will be held with the main opposition CPN-UML for amending the constitution after the completion of local level elections.The Prime Minister expressed his hope that the agitating parties will take part in the local elections even without the amendment of constitution.On the occasion, Deuba, who is also the President of Nepali Congress, vowed to develop the Pancheshwor Project.He further disclosed a plan to start the construction of a four –lane bridge over the Mahakali River soon.