The ousted envoy said his defence attache, Chit Win, had taken over the mission in "a kind of coup", two months after the military seized power in Myanmar.
In the first acknowledgement of a shoot-to-kill order by the army, a broadcast on the MRTV news channel directed at protesters said: "You should learn... that you can be in danger of getting shot to the head and back."
Its data shows that at least 25 percent of those who were killed died from shots to the head, raising suspicions they were deliberately targeted for killing.
"As of now, we are not letting anybody enter," Maria Zuali, senior government official in Mizoram state's Champhai district, told Reuters by telephone.
"They alleged that there are human rights violations and they were asked to shoot at civilians," the official said, also requesting anonymity.
Myanmar’s junta lost a tug of war over leadership of its U.N. mission in New York and the United States unveiled new sanctions targeting military conglomerates after the deaths of dozens of civilians protesting against last month’s coup.
But in the main city of Yangon, police fired rubber bullets and stun grenades to disperse protesters who had been joined by about 100 doctors in white coats, witnesses said.
Supporters and opponents of Myanmar’s military clashed on the streets of Yangon on Thursday as authorities blocked students from leaving their campus to march, a day after a first flurry of diplomacy aimed at resolving the crisis.
Much of Myanmar has been in uproar since Suu Kyi's ouster on February 1, with large street demonstrations seen in major cities and isolated villages alike.
Opponents of Myanmar’s coup took to the streets again on Saturday with members of ethnic minorities, poets and transport workers among those coming out to demand an end to military rule and the release of Aung San Suu Kyi and others.
Tens of thousands of protesters, including show-business celebrities, on Wednesday rejected the Myanmar army’s assertion that the public supported its overthrow of elected leader Aung San Suu Kyi and said their campaign would not burn out.
The junta that seized power has plunged the country into two consecutive overnight internet blackouts, as it attempts to extinguish popular resistance to its rule.