The protesters were outside Shia cleric Isa Qassim's house as part of a long-running show of support when authorities raided it. Qassim faces expulsion from the Sunni-ruled kingdom over alleged links to Iran and fomenting violence.
At least five people were killed in Bahrain on Tuesday when police opened fire on supporters of a top cleric during a raid on his house, the interior ministry said.
The incident took place in the village of Diraz at a long-running sit-in outside the home of cleric Isa Qassim, who is considered the spiritual leader of Bahrain's Shia-majority population.
The raid on Qassim's house and the subsequent use of force on protesters is likely to raise tensions in Bahrain days after US President Donald Trump said Washington's relationship with the Sunni-ruled kingdom – long strained over its human rights record – would improve.
"A total of 286 arrests were made, including fugitives who escaped from Jau Prison," the ministry said. "Several terrorists and convicted felons were also apprehended with a large number of them hiding in the residence of Isa Qassim," it added.
Witnesses had earlier told AFP that several civilians were wounded when police officers fired at demonstrators throwing stones and Molotov cocktails at security forces.
A spiritual leader
Qassim faces expulsion from the kingdom after authorities revoked his citizenship last year for alleged links to Iran and fomenting violence, charges he has denied.
Rights activists say the revocation of Qassim's citizenship was part of a crackdown by the Sunni-ruled kingdom on the mainly Shia Muslim opposition which had been seeking a greater say in running the country.
The raid took place two days after a Bahraini court convicted Qassim of financial corruption and sentenced him to a suspended one-year jail term, but a security source said the operation did not target the cleric.
The Iran conundrum
In 2011, Bahrain crushed an uprising by the Shia population. The government believes the opposition seeks to overthrow it by force and says Iran has aided in deadly militant attacks on security forces.
Iran's Foreign Minister Mohammad Javad Zarif said the raid was a consequence of Trump's visit to Riyadh over the weekend during which the US leader singled out Tehran as a sponsor of militant groups, comments that aligned with the views of predominantly Sunni Saudi Arabia.
Zarif tweeted: "First concrete result of POTUS (Trump) cozying up to despots in Riyadh: Deadly attack on peaceful protesters by emboldened Bahrain regime."
Bahraini MP Abdullah bin Huwail said in a statement that the security operation showed the government's resolve to confront an Iranian-backed security threat.
"Some areas in Diraz village had transformed into a teeming sanctuary embracing terrorists, saboteurs and fugitives from justice," said bin Huwail, the head of the parliamentary council on national foreign affairs, defence and security council.