Four men arrested in Kuwait have confessed during interrogation to being affiliated with Iran’s Islamic Revolutionary Guards Corps in a case which is likely to raise concerns about the Gulf’s vulnerability to Iranian ground attacks.

Kuwait’s defense ministry had said in early May it had arrested four suspects trying to enter the country illegally but offered few other details at the time. The interior ministry has now fleshed out that report, saying the four had used a fishing boat to reach Bubiyan Island and, during interrogation, confessed to planning hostile acts against Kuwait. Iran said the men had been on a routine patrol mission and strayed into Kuwaiti waters due to a “navigation system malfunction.”

Gulf countries are on alert for any sign of Iran-backed activities. Yesterday, the UAE placed 16 Lebanese individuals on its Local Terrorist List over their links to Iran-backed Hezbollah. On the same day, two people were sentenced to life imprisonment in Bahrain after being convicted of collaborating with the IRGC; a further 22 were given shorter prison terms or fines for supporting Iranian attacks.