US lawmakers have ordered that a system monitoring email and commercial databases for health, financial and travel information cannot be used to snoop on US citizens.

According to the New York Times, government officials have acknowledged Senate fears about the threat to personal privacy raised by the Pentagon project, known as Total Information Awareness.

Congress negotiators agreed that the project would be approved on condition that it is not used against citizens.

Under the proposed scheme, intelligence analysts could gather information from databases such as credit card transactions, airline reservations, records of telephone calls and video feeds from airport surveillance cameras.

The data would then be filtered through software that would constantly seek suspicious patterns.

With the new amendment the project could still support operations outside the US and foreign intelligence operations against non-US citizens.