New iPhone and iPad models are likely to be unveiled on Monday aimed at helping Apple keep momentum in the mobile device market. The media gathering at Apple's Town Hall auditorium in Silicon Valley could also give Apple a chance to restate its case for fighting a US government demand that it break into an attacker's iPhone.

Apple is expected to release a small-screen iPhone to encourage replacement of the 5S and 5C models, which have four-inch displays. The new device is to be called the iPhone SE or 5SE, reports said.

Specs include an improved 12MP camera, a faster A9 processor compared to the aging A7 chip in the 5s, and NFC for Apple Pay.

The rumored 4-inch iPhone "SE" could be a good deal if pricing expectations hold up. According to reports, it will be an iPhone 5s-like design with newer internals, priced between $450 and $550.

A smaller iPhone could fit the comsumers' needs in emerging economies, such as India.

A message on copies of the invitations sent to the press for the launch event states "Let us loop you in," prompting some to speculate that new bands for the Apple Watch would be among the announcements.

Reports have also said Apple is poised to introduce a new iPad tailored for use by businesses.