HONG KONG -- U.S. network equipment maker Cisco Systems warned its employees not to travel to China but then withdrew the ban, suggesting anxiety among American companies over possible tit-for-tat retaliation for the arrest of rival Huawei Technologies' finance chief.

In an internal memo obtained by the Nikkei Asian Review, Cisco told its employees that "due to recent events surrounding the arrest of a Chinese citizen in Canada on the request of United States law enforcement authorities, Cisco is implementing a restriction of all nonessential travel by U.S.-based Cisco employees into China."

The memo was sent out after Canada announced on Wednesday that Meng Wanzhou, the chief financial officer of the Chinese technology company, was arrested in the country under a U.S. extradition request, on charges of violating sanctions against Iran.

"The restriction will take effect immediately," Cisco said in the memo, adding that employees who have travel to China planned "are being advised of this restriction on nonessential travel in order to facilitate a change."

A representative at the California-based company told the Nikkei Asian Review on Friday, however, that the email "was sent in error to some employees" and "does not reflect Cisco policy."

"We have not implemented restrictions on travel and normal business travel to China continues," the spokesperson said.

Meng is the daughter of Huawei founder Ren Zhengfei, and her arrest comes as trade tensions between China and the U.S. appeared to be easing.

Curbing staff travel to China for safety considerations is not rare for international companies. Shortly after a UBS Group employee was detained in Beijing in October, the Swiss bank reportedly asked some of its bankers not to travel to China.

Citigroup, Standard Chartered and JPMorgan followed suit and asked their private banking staff to reconsider traveling to China or put their trips on hold, according to several media reports. Those travel bans were apparently short-lived.