Apple on Tuesday is expected to unveil a new lineup of iPhones, including a thinner "Air" model that could be a precursor to a folding phone next year.

The slimmed phone, which analysts said is likely to be slotted in the middle of Apple's handset lineup between less expensive iPhone 17 models and pricier iPhone 17 Pro models, will likely be the star of an event that will otherwise feature incremental upgrades to Apple Watches and other mainstay product lines.

The iPhone Air will go head-to-head against Samsung Electronics' Galaxy S25 Edge, and analysts told Reuters it could be a stepping stone toward competing with Samsung's folding phones, which are in their seventh generation.

The event at the company's Cupertino, California, headquarters comes in the midst of a global trade reordering sparked by U.S. President Donald Trump, with Apple estimating that tariffs will cost it more than $1 billion in the current fiscal quarter.

Analysts are watching closely to see whether the company will increase the price of iPhones, or seek alternative routes to making up for tariff costs such as keeping the prices of base iPhone models steady while increasing the cost of versions with more storage.

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The new iPhones will also arrive without significant upgrades to Siri, Apple's virtual assistant, which Apple has pushed off until next year.

In the meantime, analysts are closely watching to see whether Apple, which has tapped ChatGPT creator OpenAI as a partner to power certain artificial intelligence features in its operating systems, will add more AI partnerships to its lineup before the arrival of a revamped Siri. Alphabet's Google last month unveiled new phones, including a folding model, that served as a platform to show off its Gemini AI model.