Witnesses said police used tear gas, water cannon, sound bombs and buckshot to disperse the hundreds of Shiite demonstrators, who were trying to march on the capital's Pearl Square.

The square was the focus of anti-government protests last year that were supressed in a bloody crackdown in March 2011. It has been closed ever since.

Both police and protesters are reported to have been injured in the clashes along the Budiya highway.

The interior ministry said on Twitter that a "group of terrorists" attacked police with Molotov cocktails, prompting police to take "legal measures" in response.

Witnesses said protesters shouted out slogans such as "The people want the regime to fall" and "Down with Hamad" - a reference to the country's monarch, King Hamad, whose Sunni Muslim al-Khalifa dynasty has ruled the Shiite-majority Gulf kingdom for centuries.

The protests erupted after a memorial service for a young Bahraini jailed after last year's protests who died on Tuesday while serving a seven-year sentence. The government said 23-year-old Mohammed Mushima died of a blood disease, while opposition groups accused authorities of failing to provide him with proper medical care.

At least 50 people have died in nearly 20 months of unrest in the Gulf kingdom, as Bahrain's majority Shiites seek greater rights and reforms in an Arab Spring-inspired movement.

tj/sej (AFP, AP, dpa)