Bahraini authories have arrested four suspects in connection with bombings that killed two Asian expatriates in the capital Manama, the official BNA news agency reported on Tuesday.
Five bomb blasts in the capital's Gudaibiya and Adliya districts killed two Asian expatriates and wounded a third on Monday.
According to the Bahrain News Agency (BNA), the Bahraini Information Minister, Samira Ibrahim bin Rajab said the bombings were staged by terrorist groups trained outside Bahrain and based in countries including Lebanon.
She said the groups were operating under principles set by Iranian Supreme Leader Ayatollah Ali Khamenei and that 19 pro-Iran satellite media channels were inciting their supporters in Bahrain to subvert the government.
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Commenting on the arrests, the public security chief Major-General Tariq al-Hassan said: "An investigation is under way to uncover the circumstances surrounding these terrorist crimes and identify the rest of the criminals and arrest them,"
The report came hours after King Hamad ordered "the swift arrest of the terrorists who carried out the recent terrorist acts in Bahrain."
The king appealed to the public for help to "bring them to justice so they receive their punishment over this appalling act."
Prime Minister Sheikh Khalifa bin Salman al-Khalifa said: "The terrorists and vandals plotting against Bahrain will receive their punishment and the inciters will be held responsible for what happened.
"The government will not allow a stray group to destroy the nation, threaten and terrorise safe citizens," he added.
The bombings came amid persistent tensions between the kingdom's Shia majority and its Sunni rulers since the bloody crushing of month-long pro-democracy protests in March last year.
The main Shia opposition group Al-Wefaq condemned the attacks but cautioned that "due to the absence of independent human rights and media groups, it is difficult to clearly determine the truth behind the incidents."
On Tuesday, the UN Secretary-General's spokesman Martin Nesirky said in an e-mailed statement that the UN condemned the bombings in Bahrain and that such violent acts could not be justified by any cause.
"We call on all concerned to exercise maximum restraint and to refrain from any provocations. We urge all Bahrainis to come together in a spirit of national unity and to resolve differences peacefully through dialogue and reconciliation."
On Wednesday, foreign ministers from the Gulf Co-operation Counci, (GCC) are scheduled to meet in Bahrain to discuss regional issues, including the unrest in Bahrain and Kuwait, where opposition supporters have been protesting against the emir's changes to the electoral law.