India's government privately proposed in January that firms like Apple, Samsung and Google consider pre-installing its biometric identification app Aadhaar on phones, a move opposed by a group representing the smartphone giants, industry letters show. Aadhaar is a unique 12-digit identity number tied to an individual's fingerprints and iris scans, held by nearly 1.34 billion residents. It also argued that no other country apart from Russia mandates pre-installation of government apps on mobile phones. The new Aadhaar app, launched in January, allows users to update their personal details, manage profiles of their family members, and lock biometric details to prevent misuse. The letters reviewed by Reuters on the latest proposal show growing discontent among smartphone companies against app pre-installation requests by the Indian government.