US tech firm Oracle has joined the competition to buy TikTok, a popular short-video sharing app owned by Chinese firm ByteDance, the Financial Times reported on Tuesday.

Oracle has held preliminary talks with Bytedance, and said it was seriously considering acquiring the app's business in the US, Canada, Australia and New Zealand, a source familiar with the situation was quoted as saying by the Financial Times.

Moreover, the US tech firm was working with ByteDance's US investors including General Atlantic and Sequoia Capital, said the source.

Before, Microsoft and Twitter had announced they would bid on the Chinese company-owned app. Microsoft also wants to buy TikTok's global business, especially the business in Europe and India. But, ByteDance refuses to sell its business in other countries.

The new competitor in the race provided ByteDance with a credible alternative to Microsoft's offer, said the Financial Times, citing one person with direct knowledge of the matter.

Twitter and TikTok also held early stage talks, but there are doubts about the US social media firm's ability to finance the deal, said Financial Times, citing sources.

US President Donald Trump threatened to ban TikTok from operating in the country beginning Sept 15, citing national security concerns, unless it is sold to a US company.

Financial Times said that any deal would face a long list of challenges, including separating the back-end technology of TikTok from ByteDance. It is also unclear how much TikTok's US or global operations would fetch in a sale.

It is unclear whether the White House would support Oracle or Microsoft, Financial Times said.

Currently, Oracle, ByteDance, General Atlantic and Sequoia declined to comment on the deal.