The soldiers, some of whom are high-ranking officers, were detained a week ago and are being questioned over an alleged plot to attack American soldiers in the pro-US country, a security spokesman said.
"The military intelligence service is questioning some soldiers, following information concerning their intention to carry out an attack on friendly forces," said army spokesman Brigadier Yusuf al-Mulla, the Kuwaiti Kuna agency reported.
"Some of the soldiers were released after it was found out they were not involved. Others are still under interrogation," said al-Mulla, adding that less than five remain in custody.
The US has warned Americans in Kuwait that armed groups are preparing to launch attacks in the Gulf Arab state and has urged its citizens to be vigilant.
Following a December attack on a US consulate in Saudi Arabia, Kuwait boosted security around oil and other key installations and major Western embassies in the Opec nation.
A group of 20 Kuwaiti men are being tried for allegedly plotting to attack US-led forces in Iraq and Kuwait.
A Kuwaiti court is also trying another group of three Kuwaiti men accused of entering the Iraqi city of Falluja to fight US-led forces.
Kuwait is a staunch US ally which was a launch pad for the Iraq war last year. It has been cracking down on Muslim fighters opposed to the presence of US forces in the oil-rich country as well as those plotting attacks against foreign troops in neighbouring Iraq.