The four persons, including two women, were released from the Golaghat Civil Hospital after they tested negative for coronavirus in four successive tests, he said.
They will spend the next 14 days under home quarantine as a precautionary measure.
The cumulative number of coronavirus positive patients in Assam now stands at 34, which include one dead and nine patients who have been cured, he said.
Currently, 24 patients from Assam and another person from Nagaland are undergoing treatment in the state.
The condition of all of them, except a cancer patient, are stable and they would be gradually released, he said.
Meanwhile, samples of Morigaon Deputy Commissioner Rituraj Bora and Superintendent of Police Swapnaneel Deka have been taken for testing, the minister said.
The deputy commissioner, superintendent of police, the joint director of health along with two journalists of Morigaon were asked to stay in quarantine as they had come in contact with two persons who tested positive for COVID-19 on Thursday.
Golaghat with nine patients, Morigaon with six and Dhubri, Goalpara and Nalbari with four patients each have been identified as the five hotspot districts of Assam.
The other districts with positive patients are two from Silchar and one each from Kamrup (Metro), Kamrup, Hailakandi, Lakhimpur and South Salmara.
Meanwhile, oil exploration major ONGC has spent over Rs 17 lakh on COVID-19 protection gears in Assam, while the Airports Authority of India distributed masks among people in and around airports in the Northeastern region.
The Oil and Natural Gas Corporation's (ONGC) Assam asset has extended Rs 9.81 lakh for purchase of PPE kits and N95 masks for COVID-19 health care providers, officials said in Jorhat.
The contribution was made by ONGC Assam assets' Cinnamora headquarters and its Assam-Arakan Basin to Jorhat Medical College and Hospital (JMCH).
The officials said an amount of Rs 7.71 lakh has also been extended to the JMCH to purchase beds for patients and other equipment.
To ensure that no one enters a public place without wearing masks, the women welfare wing of AAI, Kalyaanmayee, has manufactured about 5,000 masks for distribution at different airports and their surrounding areas in the N-E region, an AAI spokesman said.
The target is to provide 25,000 home-made masks to the needy people, he said adding that the masks are mainly made from unused old clothes or uniforms.
"To ensure sanitisation and promote personal hygiene, we are distributing masks for free to our employees, police personnel, media, staff, security guards, garbage collectors, vendors, drivers, house-keeping staff and other stakeholders," AAI Regional Executive Director Sanjeev Jindal said at a mask distribution event in Guwahati on Thursday. DG ESB NN TDSTDS