"The state government is taking all steps to maintain the law and order situation and additional para-military forces have been requisitioned to protect the lives and properties of the people," he said.
"Central and state forces have been directed to take strong action against individuals and groups who are indulging in violence," he said.
The Chief Minister of neighbouring Mizoram, Zoramthanga, wrote to Singh, expressing concern over the violence.
"As the Chief Minister of Mizoram, a lifelong neighbour that has much in common with Manipur in terms of history and culture, I am deeply pained by the violence that has flared up in parts of your State and the underlying tension between the Meitei community and the tribals there," he wrote in the letter.
Singh said he spoke to Zoramthanga on the phone and apprised him of the present situation.
Curfew has been imposed in Meitei-majority Imphal West, Kakching, Thoubal, Jiribam, and Bishnupur districts, and tribal-dominated Churachandpur, Kangpokpi, and Tengnoupal districts.
In the Imphal valley, houses of Kuki tribals were ransacked in several areas, forcing them to flee, police said.
Over 500 residents of the Kuki-dominated Langol area in Imphal West fled their homes, and are currently staying at the CRPF camp at Lamphelpat, police said.
Some places of worship were also set on fire in the Imphal valley Wednesday night, they said.
Meanwhile, around 1,000 Meiteis of the tribal-dominated Churachandpur district fled to various areas of Bishnupur district, including Kwakta and Moirang, they said.
Over twenty houses were also burnt in Motbung area of Kangpokpi district.
Violence was also reported from Moreh near the Myanmar border in Tengnoupal district.
Lawmakers of the valley have earlier openly endorsed the demand by some Meitei organisations for ST status, alarming communities who figure in the Scheduled Tribe list.
The Meiteis inhabit the valley, which accounts for about a tenth of the former princely state's land area. They claim they are facing problems because of "large-scale illegal immigration by Myanmarese and Bangladeshis".
The hill districts which account for much of the state's land are inhabited mostly by tribals -- including the Nagas and Kukis who are mainly Christians -- and are protected from encroachment by various laws.
The neighbouring Nagaland government said it is keeping a close watch on the prevailing law and order situation in Manipur and has opened a helpline for the citizens of the state requiring evacuation from Manipur.
"A close watch is being maintained on the prevailing law and order situation in Manipur and the safety and security of people from Nagaland presently in Manipur and Imphal City," a Nagaland Home Department press release said here.
Meanwhile, at least six persons injured in clashes in Imphal have reached Kohima and are undergoing treatment in different hospitals, Nagaland Home Commissioner Abhijit Sinha said.
Meghalaya Chief Minister Conrad K Sangma too directed state government officials to evacuate students of the state studying in various educational institutions in violence-hit Manipur. Over 200 Meghalaya students are studying in Manipur, an official said and plans are afoot to airlift them, the official said.
The Meghalaya government is also putting in place a helpline number for students studying in Manipur or their family members to reach out to in case of emergencies.
Reacting to the violence, the principal opposition party Congress on Thursday alleged "Manipur is burning" as the BJP has created fissures among communities with its "politics of hate".
The party's chief Rahul Gandhi called on Prime Minister Narendra Modi to focus on restoring peace and normalcy in the state.
Congress president Mallikarjun Kharge appealed to the people of Manipur to exercise restraint and let peace prevail. "Manipur is burning. BJP has created fissures among communities and destroyed the peace of a beautiful state," Kharge said on Twitter.
In another tweet, Gandhi said he was deeply concerned about Manipur's rapidly deteriorating law and order situation. "The Prime Minister must focus on restoring peace and normalcy. I urge the people of Manipur to stay calm," he said.