In a stern warning to Egypt's leaders, Secretary of State John Kerry said the escalating violence throughout the country Wednesday had dealt a "serious blow" to political reconciliation efforts between the military-backed interim government and supporters of ousted President Mohammed Morsi.

Still, Obama administration officials signaled no change in U.S. policy toward Egypt or clear consequences for the mounting violence. The U.S. has avoided declaring Morsi's ouster a coup, a move that would force the administration to suspend $1.3 billion in annual military aid to the strategically important nation, and officials said they continued to believe that step is not in America's national security interests. They said they were engaged in a continual review of policy toward Egypt but stressed that there were no changes to announce.

Kerry, during a surprise appearance at the State Department, condemned the violence that killed at least 149 people nationwide and the reinstatement of emergency rule. He called it "deplorable" and urged Egypt's interim leaders to take a step back and calm the situation.

"It's a serious blow to reconciliation and the Egyptian people's hopes for a transition towards democracy and inclusion," he told reporters.

Kerry added that he and other administration officials had for the past week been urging the military and interim government to respect freedom of speech and assembly. But neither he nor other officials could or would outline or even hint at any consequences the failure to heed those calls would bring.

Instead, Kerry and other officials repeated their appeals for a return to dialogue.

"This is a pivotal moment for all Egyptians," Kerry said. "The path toward violence leads only to greater instability, economic disaster and suffering."

Wednesday's assault came after days of warnings by the interim administration that replaced Morsi after he was ousted on July 3. The two sit-in camps at two major intersections on opposite sides of the Egyptian capital began in late June to show support for Morsi. Protesters _ many from Morsi's Muslim Brotherhood _ have demanded his reinstatement.

Vice President Mohamed ElBaradei, a Nobel Peace Prize laureate and pro-reform leader in the interim government, resigned in protest over the assaults as the military-backed leadership imposed a monthlong state of emergency and nighttime curfew.

Kerry spoke Wednesday with ElBaradei and Egypt's foreign minister, as well as other top officials in the Middle East. He insisted that a political solution remains a viable option in Egypt, though he conceded that path was made "much, much harder" by the recent events.

Kerry did not elaborate on his call with ElBaradei, which took place after the latter had resigned. State Department spokeswoman Jen Psaki said that ElBaradei's resignation was "a concerning development" but added that Kerry had not urged ElBaradei to reconsider his decision.

President Barack Obama, on a weeklong vacation in Martha's Vineyard, Mass., was briefed on the deteriorating situation by national security adviser Susan Rice.

White House and State Department officials said the U.S. role was largely to encourage the interim government to fulfill its promises to enact political reform. The military-backed government has pledged to amend the Islamist-backed constitution adopted last year and holding parliamentary and presidential elections early next year.

"Figuring out how to encourage the interim government to make good on their promise to transition to a democratically elected government there is something that we're working on," White House spokesman Josh Earnest said. "Hopefully it's something they're working on."

The turmoil was the latest chapter in a bitter standoff between Morsi's supporters and the interim leadership that took over the Arab world's most populous country. The military ousted Morsi after millions of Egyptians massed in the streets at the end of June to call for him to step down, accusing him of giving the Brotherhood undue influence and failing to implement vital reforms or bolster the ailing economy.

Morsi has been held at an undisclosed location. Other Brotherhood leaders have been charged with inciting violence or conspiring in the killing of protesters.

At least 250 people have died in previous clashes since the Morsi's overthrow.

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Associated Press writer Nedra Picker in Edgartown, Mass., contributed to this report.