More than 20 Kuwaitis denied in court on Tuesday that they were linked to Iran and the Shiite terrorist group Hezbollah, alleging that confessions were extracted under extreme physical torture, according to AFP.
All 23 men in court told judge Mohammad al-Duaij they were systematically tortured by beatings and electric shocks, with interrogators threatening to kill them if they did not sign "prepared confessions".
Of 26 people charged, three remain at large, including the only Iranian in the case.
Prosecutors two weeks ago charged 24 of the defendants with plotting attacks against the Gulf state in collaboration with Iran and Hezbollah.
They were also charged with smuggling in and assembling explosives, as well as possessing firearms and ammunition.
A number were also charged with Hezbollah membership, AFP reported.
The accusations came after the interior ministry said in August it had uncovered a large amount of weapons, ammunition and explosives when arresting members of a "terror cell".
Iran's embassy has objected to being linked to the members of the group, and has also accused Kuwaiti media of a "systematic" campaign against relations between the two countries.
The main suspect, Hassan Abdulhadi Hassan, on Tuesday told the court that the weapons that were seized dated to the 1990-91 Iraqi invasion and occupation, and that they were handed to him by a senior member of the ruling Al-Sabah family.
"I have been hiding these arms on the orders of Sheikh Athbi Al-Sabah. We used these weapons in the resistance against the Iraqi troops," Hassan told the court, according to AFP.
Sheikh Athbi was one of the main leaders of the resistance against the Iraqi invaders.
Although all of the defendants claimed they had been tortured, they also told the judge that all traces of beatings or electric shocks have since disappeared.
Defense lawyers asked the court to refer the suspects to a neutral medical commission to examine their claims, and also called for their release.
The judge rejected their request, and set September 29 for the next hearing.
The prosecutor charged that 22 of the suspects had received explosives and weapons training so they could "achieve illegal goals".
Majority-Sunni Muslim Kuwait has been on alert since an Islamic State suicide bomber blew himself up at a Shiite mosque in the capital Kuwait city in late June, killing 27 people.