MANAMA, Bahrain — Bahrain’s king declared a three-month state of emergency Tuesday to quell a Shiite uprising, as clashes spread through the capital and surrounding villages in a showdown that drew in the region’s major powers and splintered along its main sectarian faultlines. At least two Bahrainis and a Saudi soldier died, and hundreds of protesters were injured by shotgun blasts and clubs.

A force of more than 1,000 Saudi-led troops expanded to defend the Sunni monarchy; Iran and Lebanon’s Hezbollah denounced the presence of foreign soldiers; and Washington feared for its main naval base in the Gulf. Any compromise appeared distant at best, with the latest order from Bahrain’s king and protesters’ demands for the royal family to be toppled altogether.

Doctors were overwhelmed by onslaught of patients at Manama’s Salmaniya hospital, rushing the wounded into a packed emergency room, forcing many to wait in the halls. Nurses held back tears when attending to injured young men, and doctors could barely contain their anger.

“They were all shot from close range,” said Nabeel Hameed, a neurosurgeon at the capital’s biggest hospital. He looked at an X-ray of the latest patient, shot in the chest, and added: “Yes, they do shoot to kill.”

The state of emergency in the U.S.-backed regime gives Bahrain’s military chief wide authority to battle protesters demanding political reforms and equal rights for the majority Shiites.

At Manama’s Pearl Square, the symbolic center of their revolt, thousands of protesters were still in shock over the arrival of the neighboring armies when the state of emergency was declared. Bahrain said more Gulf troops arrived Tuesday. Opposition leaders have not yet announced their next move.

“We are ready for anything, but this protest started peacefully and it will end peacefully,” said Ali Hassan, a demonstrator in the square. “We have no guns, but we will resist by remaining here as long as we possibly can.”

Secretary of State Hillary Rodham Clinton expressed alarm over “provocative acts and sectarian violence,” and said she telephoned Saudi Foreign Minister Prince Saud to stress the need for the foreign forces to promote dialogue.

“We call for calm and restraint on all sides in Bahrain,” Clinton told reporters in Cairo, where she was urging on democratic currents that chased Hosni Mubarak from power.