The conflict in western Myanmar's Rakhine state escalated in January after 13 police officers were killed in a co-ordinated attack by the Arakan Army, prompting the civilian government of Aung San Suu Kyi to order the armed forces to "crush" the group, which recruits from the largely-Buddhist ethnic Rakhine community.
In a new report on Wednesday, Amnesty said its investigations showed war crimes and human rights violations were being committed by soldiers from the Rakhine-based Western Command, which was also implicated in atrocities against the Rohingya in August 2017.
Victims also identified soldiers from the Myanmar Army's 22nd and 55th Light Infantry Divisions, units that usually operate in other parts of the country.
"Less than two years since the world outrage over the mass atrocities committed against the Rohingya population, the Myanmar military is again committing horrific abuses against ethnic groups in Rakhine state," Nicholas Bequelin, regional director for East and Southeast Asia at Amnesty International, said in a statement.
"The new operations in Rakhine state show an unrepentant, unreformed and unaccountable military terrorising civilians and committing widespread violations as a deliberate tactic."
More than 730,000 Rohingya, a minority ethnic group denied citizenship by Myanmar, were driven into Bangladesh in the bloody crackdown in 2017. A United Nations fact-finding mission has called for the prosecution of top Myanmar generals for crimes against humanity and genocide over the violence.
'Running for my life'
The latest unrest, with the military now focusing its attention on the Arakan Army, a group of an estimated 7,000 fighters battling for greater autonomy, has driven more than 30,000 people from their homes, according to Amnesty.
"There is a persistent culture of impunity," Laura Haigh, the Amnesty report's researcher, told Al Jazeera.
"It's not just a case of a few bad eggs," Haigh said. "This is very much a systemic, institutionalised problem with the Myanmar military that's not going to go away by sanctioning a few soldiers. This is not a country that's committed to accountability in any way, shape or form."
In April, the United Nations said it was "disturbed" by reports of continuing attacks on civilians in the restive state.
In its report, titled No one can protect us: War crimes and abuses in Myanmar's Rakhine State, Amnesty is urging the UN Security Council to refer the situation in Myanmar to the International Criminal Court and impose an arms embargo. It is also calling for sanctions against senior officials.
Based on 81 interviews with villagers of different ethnicities and religions in Rakhine, as well as discussions with humanitarian officials, activists and media, as well as analysis of photographs and satellite imagery, Amnesty detailed extrajudicial killings, arbitrary arrests, torture and enforced disappearances.
It said the army was involved in at least seven unlawful attacks that killed 14 civilians and wounded 29. In one incident in late January, a seven-year-old boy died after he was denied access to emergency medical treatment following a mortar attack.
In another incident in mid-March, a mortar blast wounded four people and destroyed the home of Hla Shwe Maung. Satellite imagery confirmed a building had been destroyed.
"I heard an explosion," Hla Shwe Maung, 37, an ethnic Rakhine man, told Amnesty. "It was very loud and there was a big fireball that fell around us. I grabbed my daughter in my arms … when we looked back half our house's roof was gone."
The report also detailed abuses against Rohingya, including a helicopter attack on civilians cutting bamboo. At least six people, including boys, were killed and 13 wounded.
"The helicopter came from behind the mountain," a survivor told Amnesty's researchers. "Within minutes it fired rockets. I was running for my life and thinking about my family and how I would survive."'Climate of fear with Arakan Army'
Amnesty noted the Myanmar military's "four cuts" strategy under which it aims to deny rebel groups access to "food, funds, intelligence and new recruits" was having a significant effect on the local population both in Rakhine and neighbouring Chin state.
The Chin Human Rights Organization (CHRO) last week reported increasing cases of forced labour among local villagers in the southern part of the state bordering Rakhine. Village chiefs told the CHRO, a group working to promote and protect the rights of Chin people, they were reluctant to ignore military requests for local people to act as porters for fear of retaliation.
Local people also face abuses - albeit on a smaller scale - from the Arakan Army, Amnesty said.
"The local population are caught between two forces," Haigh said. "We have this horrific abuse by the military, but there is also this climate of fear with the Arakan Army. It's always ordinary people who suffer as a result."
Amnesty said that it had put its findings to the Office of the State Counsellor and the Commander in Chief of the Myanmar Defense Services, but did not receive a reply.
Myanmar government spokesperson Zaw Htay could not be reached by phone on Tuesday and did not respond to a written message requesting comment. The military's True News unit did not respond to Al Jazeera's request for comment.
The government has responded to the reports of military abuses by restricting access to Rakhine and clamping down on the media.
Criminal complaints have been filed against at least three Myanmar-language media while Reuters' reporters Wa Lone and Kyaw Soe Oo were released this month after spending more than 500 days in jail for reporting a massacre of 10 Rohingya men and boys at Inn Din during the 2017 crackdown.
The seven soldiers convicted of involvement in those killings have been given early release having served less than a year of their 10-year sentences.
"The Tatmadaw [military] has engaged in a massive cover-up of their crimes against humanity and genocide against the Rohingya," said Phil Robertson, Deputy Asia Director at Human Rights Watch. "The only reason these seven soldiers were arrested is because Wa Lone and Kyaw Soe Oo exposed these cold-blooded murders in an investigative news story that could not be refuted.
"More than anything, the early release of these seven soldiers reveals Sr. Gen. Min Aung Hlaing and Tatmadaw commanders don't really consider the Rohingya to be human, and were never committed to seeing anyone held accountable for their crimes in Rakhine state."