Picture of Canadian and Chinese flags taken prior to the meeting with Canada's Prime Minister Justin Trudeau and China's President Xi Jinping at the Diaoyutai State Guesthouse on December 5, 2017, in Beijing. Picture taken December 5, 2017. Fred Dufour/Po
Picture of Canadian and Chinese flags taken prior to the meeting with Canada's Prime Minister Justin Trudeau and China's President Xi Jinping at the Diaoyutai State Guesthouse on December 5, 2017, in Beijing. Picture taken December 5, 2017. Fred Dufour/Pool via . Reuters / POOL

Canada's military has accused Chinese warplanes of harassing its patrol aircraft as they monitor North Korea sanction evasions, sometimes forcing Canadian planes to divert from their flight paths.

On several occasions from April 26 to May 26, aircraft of the People's Liberation Army Air Force (PLAAF) approached a Royal Canadian Air Force (RCAF) CP-140 Aurora long-range patrol aircraft, the Canadian Armed Forces said in a statement on Wednesday.

"In these interactions, PLAAF aircraft did not adhere to international air safety norms," the statement said. "These interactions are unprofessional and/or put the safety of our RCAF personnel at risk."

In some instances, the Canadian aircrew felt so at risk that they had to quickly change their flight path to avoid a potential collision with the intercepting aircraft, the statement added.

Beijing has yet to comment on the allegations.

Such interactions are of concern and of increasing frequency, the Canadian military said, noting that the missions occur during United Nations-approved operations to implement sanctions on North Korea.

The Canadian aircraft were part of Ottawa's "Operation NEON", which sees military ships, aircraft and personnel deployed to identify suspected sanctions evasions at sea, including ship-to-ship transfers of fuel and other supplies banned by United Nations Security Council resolutions.

China, which says it has enforced the UNSC sanctions, joined Russia in last week in vetoing a U.S.-led proposal for new sanctions on North Korea over its increasing missile tests.

"Under current circumstances, ramping up sanctions won't help solve the problem," Chinese foreign ministry spokesperson Zhao Lijian told a briefing on Wednesday.

China and Russia's air forces conducted a joint aerial patrol last week over the Sea of Japan, East China Sea and the Western Pacific, the first such exercise since Russia's invasion of Ukraine.