The incident between the frigate HMCS Regina and two Chinese Su-30 fighters took place Monday while the ship was in international waters off Shanghai, according to Matthew Fisher, a fellow at the Canadian Global Affairs Institute.
The Regina's captain told Fisher the Chinese jets didn't pose a danger to his ship, but Fisher's report said their flight was more aggressive than anything the (Canadian Navy) has seen before from Chinese fighter jets. CNN has reached out to the Canadian Defense Ministry for further comment.
Chinese aircraft and ships had been watching the Canadian warship, and an accompanying replenishment ship, closely after it ended a visit to Vietnam and traveled through the South China Sea, Taiwan Strait and East China Sea, Fisher reported.
Chinese Defense Ministry spokesman Ren Guoqiang on Thursday acknowledged the presence of the Canadian ships.
"We were clear about the transit of Canadian vessels through the Taiwan Strait and monitored the vessels for the whole process," Ren said.
Before the buzzing Monday, the closest Chinese jets had come to the Regina was several kilometers, according to Fisher.
Canada is just one of several US allies and partners, including France, Japan and the United Kingdom, that have been sending ships into the South China Sea or through the Taiwan Strait this year.
Beijing claims almost the entire 1.3 million square mile South China Sea as its sovereign territory and aggressively asserts its stake, with President Xi Jinping saying it will never give up "any inch of territory."
The flyby of the Canadian warship comes during a time of heightened tensions between Canada and China, following the arrest of Huawei Chief Financial Officer Meng Wanzhou in Canada in December 2018.
Shortly after Meng's detention, two Canadians were taken into custody in China, former diplomat Michael Kovrig and businessman Michael Spavor.
The Canadian government has joined with human rights organizations to call for the release of Kovrig and Spavor, describing their detentions as "arbitrary."
CNN's Lily Lee and Ben Wescott contributed to this report.