OTTAWA -- Former Canadian diplomat Michael Kovrig received a consular visit Thursday for the second time since his arrest in China last month for allegedly endangering Chinese national security, the government says.

A spokesman for Canada's foreign ministry says consular officials are pushing for more access to Kovrig, on leave from his job as a diplomat at Global Affairs Canada, and fellow Canadian Michael Spavor, who was also arrested in China last month on similar allegations.

Canadian diplomats met with Spavor, an entrepreneur, earlier this week for a second time since his arrest.

Their arrests appear to be in retaliation for Canada's arrest of Huawei senior executive Meng Wanzhou at the request of the United States. Meng's arrest and her potential extradition to the U.S. has enraged China, which has demanded her release and has warned of serious consequences for Canada.

The cases have created a deep diplomatic dispute between Ottawa and the economic superpower, which is also Canada's second-largest trading partner. Business leaders fear the dispute is already having a chilling effect on bilateral economic relations.

"The Canadian government remains deeply concerned by the arbitrary detention by Chinese authorities of these two Canadians since last month and continues to call for their immediate release," Guillaume Berube said in a statement Thursday.

"Canada continues to express its appreciation to those who have spoken in support of these detained Canadians and the rule of law."

The U.S. State Department has called for the release of Kovrig and Spavor, while Germany, France, Britain, the European Union and Australia have also issued supportive statements. Berube added that, more recently, the Netherlands, Latvia, Lithuania and Estonia have also expressed their support.

The diplomatic dispute has reverberated in Ottawa, where the Opposition Conservatives have urged Prime Minister Justin Trudeau to personally raise the cases of Kovrig and Spavor with Chinese President Xi Jinping.

In the meantime, there are further signs of erosion in the Canada-China relationship.

On Wednesday, in a published op-ed, China's ambassador to Ottawa wrote that Canada and its Western allies' calls for the release of Spavor and Kovrig are rooted in "white supremacy." Ambassador Lu Shaye's essay appeared in the Hill Times, an Ottawa publication covering Parliament and the federal government.

In the op-ed, Lu questioned whether countries such as the U.S. and Britain are truly representative of the international community and he reiterated his government's assertion that Western countries are employing a "double standard" in judging his country.

"The reason why some people are used to arrogantly adopting double standards is due to Western egotism and white supremacy," Lu wrote. "What they have been doing is not showing respect for the rule of law, but mocking and trampling the rule of law."

Some have suggested Lu should be removed from Canada for his statements.

"A shocking new low in Chinese diplomacy, and if Beijing doesn't recall Lu then Canada should consider PNG-ing him," Christopher Sands, director of the Johns Hopkins University Center for Canadian Studies in Washington, wrote Thursday on Twitter in an apparent reference to the term persona non grata.

China has described Meng's arrest as politically motivated.

The Trudeau government has repeatedly insisted she will be dealt with fairly and transparently by an independent judiciary.

But U.S. President Donald Trump undermined those assertions when he mused last month in an interview with Reuters about interfering in Meng's case if it would help him forge a trade deal with China.