Adds US State Department, paragraphs 3, 19 & 20

Dec 11 (Reuters) - At least 30 people were killed, including patients, after an airstrike by the country's ruling junta hit a hospital in Myanmar's western Rakhine state, according to a rebel group, an aid worker and a witness.

More than 70 people were injured, they said.

U.N. human rights chief Volker Turk said such attacks may amount to a war crime and called for an investigation. A spokesperson for the U.S. State Department called the reports "disturbing" and said the military government should cease violence against civilians.

The hospital in Rakhine's Mrauk U township was struck late on Wednesday by bombs dropped by a military aircraft, said Khine Thu Kha, a spokesman for the Arakan Army, which is battling the ruling junta along parts of the coastal state.

"The Mrauk U General Hospital was completely destroyed," Khine Thu Kha told Reuters. "The high number of casualties occurred because the hospital took a direct hit."

A junta spokesman did not respond to calls for comment.

Myanmar has been gripped by conflict since the military suppressed protests against a 2021 coup that unseated the elected government led by Nobel laureate Aung San Suu Kyi.

The 300-bed hospital was overflowing with patients at the time of the strike, said aid worker Wai Hun Aung, as most healthcare services across swathes of Rakhine state have been suspended amid the ongoing fighting.

"I am appalled and condemn in strongest possible terms the strikes on Rakhine hospital," the U.N's Volker Turk said in a post on X, adding he is concerned about new waves of acute violence and fear in the country.

HOSPITAL IN RUINS

On Thursday morning, the facility lay in complete ruins, with a collapsed roof, shattered columns and beams, and the bodies of victims laid out on the ground, according to images shared by Wai Hun Aung that he also posted on social media.

Reuters could not immediately verify the images.

"The remaining patients have been moved to a safe location," he told Reuters.

Soon after he heard the sound of explosions on Wednesday night, a 23-year-old resident of Mrauk U said he rushed to the scene.

"When I arrived, the hospital was on fire," he said, asking not to be named because of security concerns. "I saw many bodies lying around and many injured people."

The junta, which has the only air force in Myanmar, has been increasingly using airstrikes to hit targets inside rebel-held areas.

From January to late November, the junta conducted 2,165 airstrikes, compared to 1,716 such incidents in all of 2024, according to the Armed Conflict Location & Event Data Project.

The U.S. State Department spokesperson said Washington was deeply concerned about the Myanmar crisis and called on the junta to allow unhindered access to humanitarian assistance, release those unjustly detained, and engage in dialogue with opposition groups.

"This is essential for a secure and prosperous Indo-Pacific region," the official said.

Resistance groups formed since the coup have combined with major ethnic armies like the Arakan Army to take on the military, which is fighting the rebellion on multiple frontlines.

Since the breakdown of a ceasefire in 2023, the Arakan Army has pushed the military out of 14 of Rakhine's 17 townships, gaining control of an area larger than Belgium, according to an analysis published by the ISEAS - Yusof Ishak Institute.

Mrauk U township, in the north of Rakhine state, has been under the control of the Arakan Army since last year and there has been no recent fighting in the area, Khine Thu Kha said.

(Reporting by Reuters staff; additional reporting by David Brunnstrom in Washington, editing by Devjyot Ghoshal, Michael Perry and Deepa Babington)

((ShoonNaing@thomsonreuters.com;))