"We view recent announcements to launch a national dialogue and the release of political prisoners as positive steps towards addressing the concerns of Bahraini citizens," State Department spokesman Philip Crowley said.
King Hamad has agreed to one of the opposition's demands, ordering the release of political prisoners and the end of trials against others.
Security forces in Bahrain, home to the US Fifth Fleet headquarters, were dispatched to Manama's Pearl Square last Thursday in a raid that left four people dead. Troops were later pulled back.
The ruling Sunni Khalifa dynasty governs a restive Shiite majority near Shiite but non-Arab Iran.
It is adjacent to an oil-producing province in Sunni-ruled Saudi Arabia where Shiites have also complained of unfair leadership.
Supporters of Bahrain's Shiite-led opposition earlier marched to Pearl Square, the focal point of anti-regime demonstrations that have gripped the Gulf state since February 14. They called for the government's downfall.
Tuesday's protest came a day after pro-government Sunnis rallied at a Manama mosque, pledging loyalty to the Khalifa family, and calling on protesters to answer an invitation for dialogue.
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