Amid an escalating police crackdown on protesters in Hong Kong, Prime Minister Justin Trudeau said Monday he is “extremely concerned” about the situation.

Trudeau spoke to reporters from Toronto, where he called on Chinese authorities to listen to the protesters.

“We need to see the local authorities listen to the very serious concerns brought forward by Chinese citizens and their concerns around the decisions that the local authorities in Beijing have taken,” he said.

Hong Kong has been on edge for more than two months following protests that began in response to a proposed extradition bill, but have since morphed into calls for democratic reform and an investigation into police conduct.

On Monday, protesters descended on the Hong Kong airport, one of the largest in the world, to voice their concerns. The demonstration forced the cancellation of more than 150 flights throughout the day.

Due the large-scale demonstrations, the Canadian government recently issued a travel advisory for Hong Kong, where it urged Canadians to “exercise a high degree of caution” when travelling to the area.

“We continue to be mindful and watchful of protecting Canadian interests and Canadians, specifically in Hong Kong,” Trudeau said. “We certainly call on China to be very careful and very respectful in how it deals with people who have legitimate concerns in Hong Kong.”

Canada and China have been in a diplomatic standoff since the arrest of Huawei executive Meng Wanzhouin in Vancouver last December. Days after that arrest, China detained former diplomat Michael Kovrig and businessman Michael Spavor.

With files from The Associated Press