Myanmar's military opened fire at a Chinese Red Cross convoy carrying earthquake relief supplies on Tuesday night.
The Ta'ang National Liberation Army, an armed rebel group, said that military troops shot at the convoy of nine vehicles with machine guns in eastern Shan State.
The convoy was en route to Mandalay, the hard-hit city near the epicentre of the magnitude-7.7 earthquake that struck last Friday. No injuries have been reported.
Myanmar's junta, which said it was investigating the incident, denied shooting directly at the vehicles. It said troops fired shots into the air after the convoy did not stop, despite it being signalled to do so.
China's foreign ministry said on Wednesday that its rescue team and supplies were safe, adding that it hoped "all factions and parties in Myanmar will prioritize earthquake relief efforts".
Myanmar has been gripped by violence amid a civil war between the junta - which seized power in a 2021 coup - and ethnic militias and resistance forces across the country.
The country's humanitarian crisis has worsened significantly after last week's massive earthquake, which has killed more than 2,700 people, by the government's estimate. The actual death toll is believed to be much higher.
Multiple international aid agencies and foreign governments have dispatched personnel and supplies to quake-hit regions.
A military spokesperson on Wednesday said troops saw the aid convoy coming from Naungcho township on Tuesday night, with vehicles sporting Chinese stickers and Myanmar number plates, but had not been given prior notice of the vehicles' movement.
"When we saw the convoy, we stopped it. But they continued. We opened fire from about 200m away, but they didn't stop," he said.
"At about 100m away, we fired three shots in the air, after which the vehicles turned back towards Naungcho."
China's Blue Sky Rescue Team, which has been providing rescue support in Mandalay, had been given a security cover when they travelled through this route, the spokesperson said.
He added that when international agencies want to give aid, they need to inform the Myanmar government.
The TNLA, which was escorting the Red Cross convoy, said they had informed the military council about going to Mandalay.
After retreating to Naungcho, they would be continuing their journey, the group said in a statement.
Rebel groups have unilaterally announced a ceasefire to support earthquake relief efforts. But the military has refused to do the same.
Hours after the quake struck on Friday, the junta launched an air strike in Naungcho township that killed seven people.
Junta chief Min Aung Hlaing has said that since ethnic armed groups were still "training in preparation for attacks", the military would continue its "necessary defence operations".
The UN described the airstrikes as "completely outrageous and unacceptable".
