The detentions of the Canadians - including one disclosed on Wednesday - followed the Dec. 1 arrest in Vancouver of Meng Wanzhou, chief financial officer of the Chinese telecommunications giant Huawei Technologies Co Ltd.. The arrest was made at the request of the United States, which is engaged in a trade war with China.

Trudeau has been under pressure to take a more robust stand on the detentions, but said at a news conference: "Political posturing or political statements aren’t necessarily going to contribute. They might actually hinder Canadians’ release. We’re going to take every situation carefully and seriously.

"Canadians understand that even though political posturing might be satisfactory in the short term to make yourself ... feel like you're stomping on a table and doing something significant, it may not directly contribute to the outcome we all want, which is for these Canadians to come home safely."

Trudeau said he was asking China for more information on the detentions. No details have been given on the latest, but Trudeau said it was "a very separate case" from last week when former Canadian diplomat Michael Kovrig and businessman Michael Spavor were detained amid the diplomatic quarrel triggered by Meng's arrest.

The National Post newspaper said the latest detainee was a Canadian woman who was teaching English in China and was held because of "visa complications."

Huawei is the world’s biggest supplier of telecoms network equipment and second-biggest smartphone seller. The United States has been looking since at least 2016 into whether Huawei shipped U.S.-origin products to Iran and other countries in violation of U.S. export and sanctions laws, Reuters reported in April.

The Canadian government has said several times it saw no explicit link between the arrest of Meng, the daughter of Huawei’s founder, and the detentions of Kovrig and Spavor. But Beijing-based Western diplomats and former Canadian diplomats have said they believed the detentions were a "tit-for-tat" reprisal by China.

Bob Rae, Canada's special envoy to Myanmar and a former Liberal Party leader, tweeted on Wednesday that "there are no coincidences" and said the detentions looked "too much like hostage taking."

An official at the Chinese Embassy in Ottawa said the embassy had no information to release on the issue.

Meng is accused by the United States of misleading multinational banks about Iran-linked transactions, putting the banks at risk of violating U.S. sanctions. She was released on bail in Vancouver, where she owns two homes, while waiting to learn if she will be extradited to the United States. She is due in court on Feb. 6.

U.S. President Donald Trump told Reuters last week he might intervene in the case if it would serve national security interests or help close a trade deal with China.

The comments upset Canada, which warned the United States against politicizing extradition cases.

Trudeau said a decision on whether to use Huawei equipment in Canada's 5G mobile network should be made by experts and not influenced by politics.

BUYING TIME

A source with direct knowledge of the situation said senior officials at the Canadian Foreign Ministry had held many meetings about the detainees but that a formal task force had yet to be created.

"At this point, Canada is trying to buy time by stressing it has a rules-based order and an independent judiciary," said the source, who declined to be identified because of the sensitivity of the situation.

A second source said Canada was concerned that the detainees were in the hands of the powerful security authorities.

"Even if there were voices of reason in the Chinese system saying: 'Are you crazy? The Canadian government cannot order a judge to release Ms. Meng,' the security voices are going to trump them," the source said.

Philip Calvert, a former diplomat in China and now a research fellow at the University of Victoria, said at least the first two detentions were indicative of "the way China often engages internationally in situations like this."

"The people making the decisions in Beijing really think when push comes to shove, they can put pressure on Canada to override the system," he said.

Flavio Volpe, president of Canada's Automotive Parts Manufacturers' Association, said on Wednesday he had spoken with a few Chinese automakers that are now delaying a decision to set up production facilities in Canada. The automakers, which Volpe declined to name, had been weighing whether to sell cars built in Canada to the North American market.

The last time Canadians were detained in China for security reasons was in 2014 when Kevin and Julia Garratt, who ran a coffee shop in northeastern China, were held near the border with North Korea. She was released and left the country, while her husband was charged with spying and stealing state secrets before being released and deported two years later.

The arrest of the Garratts came shortly after a Chinese businessman was picked up on a U.S. warrant in Canada.