Gunmen shot journalist Tongam Rina of the Arunachal Times from close range when she was entering her office at about 6.15 pm, police said.
Thirty-four-year-old Rina is the associate editor of Arunachal Times, a popular daily and the first English newspaper of the state owned by former chief minister Gegong Apang.
Her backbone and intestines were affected by the bullets, police said.
Chief Minister Nabam Tuki rushed to the Ramakrishna Mission Hospital where she is undergoing an operation. The police have launched a manhunt to arrest the culprits, sources said.