A vehicle bomb carrying chemical substance detonated outside a US military base in northeast of Baghdad, the US military said on Monday.

The attack took place on Sunday in the vicinity of an entrance outside Forward Operating Base Warhorse near Baquba, some 65 km northeast of Baghdad, a statement said.

The blast did not cause any damage to the entrance or the base, it added.

However, the statement said that following the attack" there was an unconfirmed report of off-color smoke in the vicinity of the explosion and a number of soldiers reported minor respiratory irritations and watery eyes."

Some insurgent groups frequently used chlorine gas as chemical weapon in Iraq, mainly in the volatile western province of Anbar.

Sometimes, such attacks inflicting massive loss of life as the gas burns the skin on contact and can be fatal after a few breaths.

On Sunday, the US military announced the death of 14 of its soldiers across the war-torn country, including four in a single roadside bombing.

So far, at least 16 US soldiers have been killed in Iraq this month, bringing the US death toll to more than 3,494 since the outbreak of US-led invasion to Iraq in 2003.

(Xinhua News Agency June 4, 2007)