The injured are Surendra Kumar Patel of Ramgram, Komal Yadav and Bikash Harijan of Manhari-8 and Rama Aaya of Dedhgaun-8. All the injured are receiving treatment at Prithvi Chandra Hospital.
Police fired rubber bullets at demonstrators after they vandalized house of UML lawmaker Baijanath Chaudhary in Tilakpur Magarbudha.
DSP Som Thapa said police opened fire to maintain order.
Protesters have obstructed the East-West Highway against the demarcation of provinces.
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