Hundreds of Iraqis have meanwhile demonstrated outside the Bahraini embassy in Baghdad in support of the Bahrain protesters
Saudi Arabia on Wednesday defended the actions of Bahraini authorities who opened fire on a protest by supporters of a top Shia cleric, killing five people.
The security of Bahrain "is an integral part" of Saudi security, the official Saudi Press Agency quoted a source in Riyadh's foreign ministry as saying.
"The source affirmed the support of the Kingdom of Saudi Arabia for the measures being taken," including in Diraz village near the capital Manama, it said.
These measures are to "address all terrorist attempts aimed at destabilising and damaging" security and order, it added.
The Sunni-ruled Gulf state, where Shia are a majority, has been shaken by unrest since 2011, when Bahraini authorities backed by a Saudi military force crushed Shia-led protests.
— هيكل بافنع (@BaFana3) May 24, 2017
Demonstrators were demanding a constitutional monarchy and an elected prime minister.
Bahrain's interior ministry on Tuesday said five people died among "the outlaws" in the Shia village of Diraz, where supporters of Shia cleric Isa Qassim were holding a sit-in outside his home.
Witnesses had earlier told AFP that several civilians were wounded when police fired at demonstrators throwing stones and Molotov cocktails at security forces.
Bahrain is located just across a causeway from Saudi Arabia, most of whose Shia minority live in Gulf coast or other eastern communities.
Shia in Saudi Arabia, who have long complained of marginalisation, also began protesting in 2011.
Sporadic security incidents that have continued since then escalated this month in the Shia town of Awamiya.
Authorities said a policeman died in a rocket propelled grenade attack on 16 May, while at least two other people were earlier shot dead in unrest centred on a neighbourhood slated for redevelopment.
A resident of the area reported gunfire early on Wednesday.
Iraqis protest outside Bahraini embassy
Meanwhile, hundreds of Iraqi citizens staged a protest on Wednesday outside the Bahraini embassy in Baghdad in support of the Bahraini protesters, reported Iraqi media.
The protesters called on the Bahraini government to end its "oppression against its people", Iraqi News reported on Wednesday.
The demonstrations came in response to calls on Tuesday by Shia cleric Muqtada al-Sadr who asked his followers to protest the arrest of Qassim.
Earlier on Tuesday, Arabic media reported that Bahraini security forces invaded Qassim’s home located in Manama and arrested everyone inside.
The raid came shortly after a top criminal court sentenced Qassim to one year in prison and froze his assets.
It was not clear whether Qassim, who was stripped of his citizenship in 2016, was among those arrested.