China says it will complete land reclamation projects on its disputed South China Sea territorial claims as planned within "upcoming days."

A statement from the Foreign Ministry statement Tuesday said China would build infrastructure to carry out functions ranging from maritime search and rescue to environmental conservation and scientific research.

Apart from satisfying defense purposes, it said the main purpose of such projects was civilian in nature and not targeted at any third parties. China says the projects are legal, justified and within the scope of Chinese sovereignty.

The reclamation work has raised tensions with the United States, and Vietnam and other countries in the region which fear China will use the artificial islands as military bases and to assert control over navigation in the South China Sea.