Apple will launch its next iteration of iPhone on 15 March, and the device will be available for sale in the same week, 9to5Mac has reported.

The new models to be introduced at an Apple event on 15 March are a new 4-inch iPhone dubbed the "iPhone 5se" and a new iPad Air, the publication said citing sources. However, Apple may not offer pre-orders for the new devices.

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And what is the strategy behind launching new models close on the heels of bigger models like iPhone 6s and iPhone 6sPlus?

"The new 4-inch iPhone 5se is designed to spur iPhone hardware upgrades for customer seeking newer technologies and faster devices without the need to upgrade to the far larger 4.7-inch and 5.5-inch iPhone 6s and 6s Plus screen sizes," the portal says.

For example, while the iPhone 5se's body will be identical to the 2013 iPhone 5s, it could include Apple's latest A9 and M9 processors. Speculation is that besides the faster A9 processor, it could also feature M9 chip with support for always-on Siri activation, more storage, updated cameras, the ability to take Live Photos, and an NFC chip for Apple Pay.

The new iPad features may include a variant of the A9 processor, an upgraded camera system, and potentially a rear flash for brighter photos, the report says.