Myanmar's military horribly tortures political prisoners, journalist Yuki Kitazumi said after his return to Japan.

"I have heard from many inmates that they would be first blindfolded, have their hands handcuffed behind their back, and be forced to kneel on concrete floors," Yuki Kitazumi told reporters in an online news conference hosted by the Foreign Correspondents' Club of Japan on Friday. "If they would deny any of the accusations being made against them, they would be struck with a stick. The military continued this for two or three days straight."

Kitazumi was deported to Japan on May 14, after spending nearly a month at Yangon's Insein Prison, where many political prisoners are being kept. He was detained on April 18 and taken into custody the next day. A computer, camera, and other items were confiscated. Most of his belongings were returned upon his deportation.

The freelance journalist was charged under a law that criminalizes comments that could cause fear or spread false news. He denied any wrongdoing. "I was fulfilling my role as a journalist," he said, "conveying what was happening."

While being interrogated, he was never presented with an article, video or other pieces of evidence, he said. "Arresting me was a way to convey a threat to other foreign [journalists]," he said.

Kitazumi was confined in a cell built during the British colonial period (1824-1948). He said it measured about 4 meters by 2.5 meters. The wing he was kept in has been used for detaining VIPs such as former government officials, a famous actor, renowned Burmese journalists and media executives.

He was not subjected to torture; interrogators only pounded a desk in a threatening manner while questioning him. "What was difficult for me was the sweltering heat of Myanmar, which often reaches 40 C," he said. April and May are the hottest months of the year in many parts of Southeast Asia, and his cell's brick walls preserved the heat day and night.

He was fed three times a day, with meals usually consisting of steamed rice, vegetable soup and pumpkin curry.

In the cell, he was denied the use of any writing materials but managed to invent a pen using a feather and concentrated coffee.

According to Myanmar state-run television, Kitazumi was released "in consideration of cordial relations between Myanmar and Japan up to now and in view of future bilateral relations, and upon the request of the Japanese government special envoy on Myanmar's national reconciliation."

"It was the result of efforts made by Ambassador Ichiro Maruyama and others going through various channels," Japan Foreign Minister Toshimitsu Motegi said.

On Thursday, Motegi told Nikkei that Japan will consider cutting off all official development assistance to Myanmar. "I do not believe that cutting off ODA will be enough to resolve the issue, but it will indeed be a strong message," Kitazumi said.

Japan's ODA projects in the country should be reconsidered, he said, as they are unlikely to operate efficiently under a military regime.

Kitazumi was a Nikkei staff writer in Japan before he moved to Myanmar in 2014 and became the chief editor of a local informational magazine that was published in Japanese. He also worked as a freelance journalist in the country and covered social issues for his own media production company, Yangon Media Professionals.

The detention that led to his deportation was his second since the coup, which took place on Feb. 1. The first time came on Feb. 29, when the 45-year-old freelancer was apprehended while covering an anti-coup protest in Yangon. His detention that time was brief.

Myanmar's military had little trouble usurping power from State Counselor Aung San Suu Kyi. The military, led by Gen. Min Aung Hlain, has since cracked down on dissent, and arrested and killed pro-democracy demonstrators.

The Assistance Association for Political Prisoners, a human rights organization watching the situation in Myanmar, as of May 20 has counted 4,212 politically motivated arrests and 810 deaths. The number has been rising as the military firms its grip on all levers of power.

Leaders of the Association of Southeast Asian Nations on April 24 held an ad hoc summit to discuss Myanmar. The leaders, including Myanmar Senior Gen. Min Aung Hlaing, came up with a "five-point" consensus that demands Myanmar accept a special ASEAN envoy to monitor the situation.

After the meeting, the military said it would only accept the envoy after it stabilizes the country. The situation remains fluid.

Kitazumi said inmates were using all possible means to learn about current happenings outside the prison. Some asked their lawyers for information, while others listened to what correctional officers were saying. "People in house arrest like Aung San Suu Kyi could be very much aware of the situation in Myanmar if they have knowledgeable informants," he said.

The journalist also reminisced about his time in Southeast Asia. "This was a place where I lived for six years, it is my second home," he said.

Speaking out on the situation, he said, will only reduce the chances that he could ever return. But "I promised the inmates I would let the world know," he said. "My mission is to convey the truth of what is happening."