Canada has reportedly been urged by the Ministry of Public Security to deport a former Bank of China manager accused of embezzling 1 billion yuan of clients' deposits. The latest attempt by Beijing to extradite corrupt officials from overseas follows a souring in its relationship with Canada after a spate of diplomatic hiccups. Xinhua reported earlier this week that the extradition of Gao Shan, formerly the head of a BOC sub-branch in Heilongjiang's provincial capital, Harbin, had been requested by the ministry. Gao's case first came to light in 2005 when Northeast Expressway, a highway company, discovered nearly 300 million yuan was missing from its BOC account. Gao is accused of transferring large sums of money overseas before fleeing China. Official reports have estimated the embezzled amount at between 800 million and 1 billion yuan. His whereabouts had remained unknown until a Heilongjiang court tried other suspects involved in the case this month. Zhang Xiaoguang, a former director of Northeast Expressway on trial for corruption, told the Baicheng City's Intermediate Court on January 18 that Gao and another associate, Li Dongzhe , were 'under the control of' Canadian police, the New Culture Newspaper reported. Zhang was also quoted as saying Canadian police had visited Heilongjiang to investigate Gao's case. In a report published yesterday, Canada's Globe and Mail quoted police sources as saying that Canadian police were still investigating and did not have Gao in custody. Rachael Bedlington, head of public affairs at the Canadian embassy in Beijing, declined to confirm or deny the extradition request. China and Canada do not have an extradition treaty. 'But it doesn't mean it's not possible to extradite a person [back to China],' Ms Bedlington said. The Ministry of Foreign Affairs said it had no details of the request. China's attempts to extradite its most-wanted fugitive, Lai Changxing , have been unsuccessful since he fled to Canada in 1999 and claimed refugee status. That extradition request and Canadian Prime Minister Stephen Harper's public criticism of China's human rights record were said to be behind strains in Canada's relations with the mainland. A bilateral meeting between Mr Harper and President Hu Jintao during the Apec summit in Hanoi was cancelled last year.