Yes you need to add 120x120 high resolution icon now If you want to target only iOS 7, you just need 76 x 76, 120 x 120 and 152 x 152 icon sizes. If you want to target also iOS 6, you’ll need 57 x 57, 72 x 72, 76 x 76, 114 x 114, 120 x 120, 144 x 144 and 152 x 152 icon sizes. Without counting Spotlight and Settings icon if you don’t want the OS to interpolate them!

As per this article.

UPDATE:-

As par apple Guide line App-icon OR Icon and Image Sizes

Icon dimensions (iOS 7 and later)

Icon dimensions (iOS 6.1 and earlier)

Create different sizes of the app icon for different devices. If you’re creating a universal app, you need to supply app icons in all four sizes.

For iPhone and iPod touch, both of these sizes are required:

• 120 x 120 pixels

• 60 x 60 pixels (standard resolution)

For iPad, both of these sizes are required:

• 152 x 152

• 76 x 76 pixels (standard resolution)

Now set this In to Project:-

• Create new icon with 120px with high-Resolution and 60px as regular as above that Apple doc mention and set name For Example icon-120.png and icon-152.png.

• Put this icons in to you Project Resource Folder and add this icon into Project

• After This click on ProjectName-Info.plist and Find icon files Row if you can't find then Add by clicking (+) sign and select icon files then set all icon images Like Bellow.

Now Archive & Distribute you project as we did same for submission App binary in to app store. Hope now you can submit you app without any icon issue.