Bahrain said on Thursday it had seized explosives and bomb-making materials planned for use in Bahrain and neighbouring Saudi Arabia in what it said was an attempt to use its borders as a base for attacking targets in the region.
In a statement, police chief Major-General Tariq al-Hasan said the techniques used in the manufacture of the explosives bore "clear similarities" to methods used by what it called proxy groups of Iran's Islamic Revolutionary Guards Corp (IRGC).
Bahrain often accuses Shi'ite Muslim theocracy Iran of seeking to subvert the Gulf Arab island monarchy.
Iran denies interfering in Bahrain, although it acknowledges it does support opposition groups seeking greater political and economic rights for Bahrain's Shi'ite Muslim community.
Hasan said the seized items, including powerful explosive C4, commercial detonators, advanced circuitry, chemicals and mobile phones, "represent a significant escalation in attempts to smuggle explosives material into Bahrain".
The June 6 seizure in the Dar Kulaib district was made possible by information arising from the capture in May of a vehicle containing similar explosives as it was being driven across the causeway that links Bahrain to Saudi Arabia, he said.
Bahrain has reported a growing number of attacks using home-made explosives, some of them deadly, in the past two years.
Hasan added that the June 6 operation and previous such seizures "point to an emerging trend. The professionalism with which these seized materials are assembled and concealed is a clear indication of international support and sponsorship."
"Of greater concern, however, is the fact that these sophisticated bomb-making materials were destined for Saudi Arabia, a sign that extremists are increasingly using Bahrain's borders as a launch pad for terrorists seeking to carry out attacks elsewhere in the region."