Protesters, police clash in Bahrain, Yemen and Iran

CAIRO — Tens of thousands of protesters faced club-wielding security forces Monday in Bahrain, Yemen and Iran in what experts said may be shaping up as a pro-democracy wave ignited by the revolts that drove Egypt and Tunisia's autocratic rulers from power.

At least one protester was confirmed killed in Bahrain, and there were unconfirmed reports of several deaths and hundreds of arrests in Tehran, where anti-government marchers chanting "death to dictators" staged their largest demonstration in more than a year.

The Obama administration spoke out for the Iranian protesters, in contrast to relatively mild initial statements it issued when unrest erupted there after disputed presidential elections in 2009.

"Let me very clearly and directly support the aspirations of the people who are in the streets in Iran today," Secretary of State Hillary Clinton said after a Capitol Hill meeting with House Speaker John Boehner, R-Ohio.

"What we see happening in Iran today is a testament to the courage of the Iranian people and an indictment of the hypocrisy of the Iranian regime, a regime which over the last three weeks has constantly hailed what went on in Egypt," Clinton said.

In Bahrain, a Manhattan-size emirate with a population of 738,000, security forces attacked peaceful protesters to prevent them from massing in Manama, the capital, according to news reports and Internet posts.

Twitter feeds spoke of police firing tear gas, bird shot, rubber bullets and live ammunition.

In Yemen, security forces and pro-regime groups clashed for the fourth straight day with university students, journalists and others demanding democratic reforms and the ouster of President Ali Abdullah Saleh, who has ruled the impoverished nation at the tip of the Arabian peninsula for 32 years.