The United States has said it is not certain whether Saddam Hussein is alive, following an Al Jazeera broadcast of a tape said to be from the deposed Iraqi leader.

On the tape, dated 14 June, the ousted Iraqi President says that resistance groups are being built up on a large scale throughout the country. The voice also says that he is living in Iraq.

A White House spokesman has said regardless of whether it is Saddam Hussein's voice on the tape, he is out of power.

The release of the tape follows yesterday's offer by US forces of a $25m reward for information leading to his capture, or proving his death.

Earlier, another US soldier has been shot dead and 19 others wounded in two separate attacks. in Iraq. The soldier who died was shot by a sniper in Baghdad.

The second attack took place against a US base near the town of Balad, some 45 miles north of Baghdad.

It is believed a mortar was fired into the base.