MANAMA, Bahrain (AP) — Riot police in Bahrain have fired tear gas and stun grenades to disperse thousands of marchers trying to reach a heavily guarded square that was once the hub of their anti-government uprising.

The clash followed ceremonies Monday to mark the end of Shiite religious commemorations known as Ashoura. It was the heaviest clash in months near Pearl Square, where Shiite-led protesters gathered in February 2011 to demand a greater political voice in the Sunni-ruled Gulf kingdom. It has since been closed off.

The street battles spilled into surrounding Shiite neighborhoods.

Bahraini authorities have outlawed protest marches in an attempt to quell growing violence in the more than 21-month-old unrest. Shiite leaders say they plan more marches in defiance of the order.

Bahrain is home to the U.S. Navy's 5th Fleet.