SHANGHAI/BEIJING (Reuters) - Online brokerages Futu Holdings and UP Fintech Holding, known for helping Chinese investors buy global stocks, have told clients that night trading of U.S. shares would be suspended on Tuesday after a surge in global market volatility.

The brokers attributed the move to notices they received from U.S. service provider Blue Ocean, without giving details. Blue Ocean gives clients electronic access to trade U.S. stocks between 8:00 pm and 4:00 am ET (0000-0800 GMT), Sunday to Thursday, and access to data.

Trading during other hours will not be affected, the brokerages said. Blue Ocean did not immediately respond to a request for comment.

Global stocks rallied on Tuesday, reversing some of the rout triggered the previous day by fears of a U.S. recession and disappointing results of some tech giants, after central bank officials moved to soothe investor nerves.

Futu said in a notice to clients that Tuesday's trading suspension was the result of "prudent consideration" after the notice from Blue Ocean.

UP Fintech, also known as Tiger Brokers, made a similar statement, adding that orders placed between 1:45 a.m. and 4:00 a.m. ET (0545-0800 GMT) on Aug. 5 had also been cancelled.

The company said it had dealt with the affected orders properly and apologized to clients.

The two brokers last year removed their apps in mainland China after Chinese regulators banned the companies - which do not have securities licences in China - from soliciting onshore clients via the Internet.