China's civil aviation authority said on Thursday that four airlines based in the United States have not fully corrected how they refer to Taiwan on their booking websites, and it will keep an eye on what they do in the next two weeks.

On April 25, the Civil Aviation Administration of China demanded that 44 foreign airlines review their websites and apps and cease listing the Hong Kong and Macao special administrative regions and Taiwan as independent countries.

By Wednesday's deadline, the 44 airlines had all made some changes and 40 of them have made the full change demanded by China, the CAAC said in a statement on Thursday.

American, Delta, Hawaiian and United airlines submitted rectification reports to the CAAC on Wednesday, saying that they have started making corrections and asked the CAAC to check the websites in two weeks.