Bahrain has accused Iran's Revolutionary Guards of providing opposition fighters with explosives training in order to carry out attacks in the Gulf kingdom, also announcing that it had arrested five suspects.
Chief prosecutor Osama al-Oufi said the intelligence service reported last month that "Bahraini Ahmed Mahfuz Moussawi, currently living in Iran, had planned terrorist bombing operations targeting institutions and places vital to the sovereignty and security of the kingdom."
"He is also accused of jeopardising the safety and security of the kingdom, injuring persons, terrorising citizens and residents, disturbing public peace, spreading chaos, and preventing government institutions and authorities from performing their functions," the statement said.
In statements quoted by state news agency BNA, he added that five people had been arrested and "admitted joining a group to carry out terrorist attacks... and travelled to Iran to receive training in Revolutionary Guards camps and then received sums of money."
An arrest warrant has been issued for Moussawi and a group of people associated with him.
The chief prosecutor said two men had been arrested while they were "on a boat receiving weapons, munitions and explosives to be smuggled from a boat at sea into the country. Three other accused group members were also arrested."
On Monday, Bahraini authorities said they had seized a boat smuggling explosives made in Iran and Syria into the country.
Bahrain is ruled by a Sunni Muslim dynasty but has a population that is majority Shia.
The government crushed a mostly Shia-led uprising in 2011 and has long accused predominantly Shia Iran of meddling in its affairs.
Since the 2011 uprising, which called for democratic reforms, demonstrations have regularly been held in Shia villages around the capital, often sparking clashes with security forces.
At least 89 people have been killed in Bahrain since the protests began, according to the International Federation for Human Rights.
Several bomb attacks have taken place in recent months, including one that targeted a Sunni mosque close to the royal court in July but caused no casualties.
Tensions escalated over the weekend as authorities interrogated top Shia opposition leader Ali Salman.
The head of the main Shia bloc Al-Wefaq was released after a day of questioning, but was charged with incitement to religious hatred and spreading false news endangering national security.