BEIJING (AP) — Australia on Saturday accused the Chinese navy of likely causing minor injuries to Australian naval divers by operating its sonar while they were trying to clear fishing nets from their ship’s propellers.

The Australian government has expressed its serious concerns to the Chinese government over what it called the unsafe and unprofessional conduct earlier this week, Defense Minister Richard Marles said in a statement on his official website.

There was no immediate comment from the Chinese side. The U.S., Canadian and Australian militaries have complained multiple times about what they say have been dangerous actions by the Chinese navy and air force in the western Pacific. Analysts fear a collision or other accident could spark an international incident and escalate into conflict.

The HMAS Toowoomba stopped in international waters on Tuesday in Japan’s exclusive economic zone after fishing nets became entangled in its propellers, the defense minister’s statement said. The naval frigate had been helping to enforce U.N. sanctions in the region.

As diving operations were underway, a Chinese destroyer moved toward the Australian ship and was detected operating its hull-mounted sonar in a way that posed a risk to the divers and forced them to get out of the water, the statement said.

“The divers ... sustained minor injuries likely due to being subjected to the sonar pulses from the Chinese destroyer,” it added.

Sonar uses sound waves to obtain an image in the water. At high levels, those can cause dizziness, hearing damage other organ damage.

Australian Sen. James Paterson, a member of the opposition Liberal Party, noted the incident came shortly after a visit by Prime Minister Anthony Albanese to Beijing to improve his country’s ties with China.

“On one hand, China says it wants a better relationship with Australia and on the other hand it takes dangerous maneuvers that put the safety of Australian personnel at risk,” he told reporters.