Two of the new patients are BSF personnel. The northeastern state's virus count now stands at 104, they said.
In a series of tweets on Wednesday night, Chief Minister Conrad K Sangma said that of the three other patients, two had recently returned from Delhi and Bihar.
Of the 104 cases, 57 are active while 45 people have recovered and two patients have died, a health official said.
With the number of infected BSF personnel posted in the state rising to 27, the health authorities have ordered tests on the personnel of the border force.
Twenty-seven Border Security Force (BSF) personnel and a high-risk contact of one of them have tested positive for COVID-19 while test results of 108 others are awaited, Director of Health Services, Amar War, said.
Rapid diagnostic tests have been conducted on 1,006 BSF personnel, he added. JOP ACD ACD