Google announced a new lineup of mobile devices, using alliances with Korean electronics makers Samsung and LG, to step up a challenge to Apple in the market for tablets and smartphones.

The new phone, developed with LG, is called the Nexus 4 and boasts a 4.7-inch display and tools for sharper photo taking, Google said yesterday.

A new tablet, made by Samsung, is called Nexus 10, has a higher resolution screen and costs $399 to $499, depending on how much storage it includes. Both are part of the Nexus line of electronics, which showcase the most advanced features of Google’s Android software.