Fifteen people were injured in the incident at Camp Udairi, one of whom suffered a knee injury and was medevaced to Germany while the remaining 14 had minor scrapes and resumed work, the spokesperson told AFP.

The truck driver had sustained two gunshot wounds, to the upper chest and shoulder, and was in "critical condition," the spokesperson said.

A Kuwaiti security source meanwhile said the driver was an Egyptian electrician employed at the camp, adding "we don't know yet if it was an accident or an attack."

Kuwaiti security authorities are unable to get access to the man, who is still being investigated by US Military Police, the source said.

Another security source had earlier described the truck driver as a disgruntled employee but stressed that the incident was not being regarded as a "terror" attack at this stage.

"Initial reports show there was a truck driven into a group of soldiers" in one of the many US camps in the north of the country, US army spokesman Colonel Gregory Julian told AFP soon after the incident.

"We're trying to determine how many were involved and who was involved," Julian said.

Last week, a US soldier was detained on suspicion of lobbing grenades into tents at a US army camp in northern Kuwait, killing two servicemen and injuring some 11 others.

US forces in Kuwait have been involved in a series of attacks, one fatal, since last October when two Kuwaiti gunmen killed a US marine and wounded another during wargames.

Tens of thousands of US troops are based in Kuwait, the main launchpad for the US-led invasion of Iraq.

WAR.WIRE