Chief Minister Conrad K Sangma said only people engaged in essential services will be permitted to enter the state during the period.
"To reduce the burden on our health workers and administration engaged in intensive surveillance for the past four months, the state government has decided to close all the entry points to the state from July 24 to 31," he said.
The entry points of Byrnihat, Ratacherra, Bajengdoba, Tikrikilla, Mirjumla and Hallidayganj will be shut during the period. They will be reopened on August 1, Sangma said, adding that the one at Byrnihat will be shifted to a new location to ensure smooth movement of traffic.
The state government has also decided not to allow wedding receptions in the districts of East Khasi Hills and Ri Bhoi for the time being, he said.
"Only solemnisation of marriages in places of worship will be permitted, with strict adherence to social distancing norms," the chief minister said.
The decision in this regard comes after 10 of the 41 people who had attended a wedding reception tested positive for COVID-19. As many as 200 primary contacts of the patients were identified and isolated during a two-day lockdown imposed in Shillong.
The 16 fresh cases registered in the past 24 hours include nine Army and four Assam Rifles jawans, and three Border Security Force (BSF) personnel, Director of Health Services, Aman War, said.
The fresh infections have taken the number of active cases in the state to 305, while two patients have died, he said.
A BSF personnel has recovered from COVID-19, taking the total number of persons cured of the disease to 47, War added.