Washington is "closely following" political developments in Egypt, US State Department spokesperson Victoria Nuland said during a press conference held in Washington D.C. on Thursday.
Coming days after President Barack Obama's statement on the issue, Nuland said there had been continuous calls by Washington for a "peaceful and comprehensive" dialogue between Egypt's Islamist government and opposition forces.
"We are still concerned about the absence of common ground among the different political groups, but the current constitutional crisis has to be solved peacefully," Nuland stated.
Obama has called for calm in Egypt to peacefully overcome the power struggle between Islamists and the opposition which heated up after the announcement of President Morsi's constitutional declaration, White House spokesman Jay Carney said late on Monday.
"We've raised concerns about some of the decisions and declarations that were made on 22 November," he added. "And we continue to engage with the Egyptians on this. I think the important issue here is the Egyptian people want a government that reflects their will."
On Thursday, Morsi, who hails from the Muslim Brotherhood, issued a decree making all his decisions immune from legal challenges for a six-month period.
The decree also protects the Islamist-led Constituent Assembly (tasked with drafting a new constitution) and the Shura Council (the upper house of parliament) from being dissolved by the judiciary - which is currently reviewing the constitutionality of both bodies.
Morsi's surprise move prompted uproar among the opposition, which described it as an attack on democracy.
Egypt's political crisis came only days after Morsi was being toasted by world leaders for his diplomatic skill and moderation in helping forge a ceasefire between Gaza's Islamist rulers and Israel following a bloody eight-day conflict.
Morsi was elected Egypt's first Islamist leader in June, but he is still vying for control over the country.
The crisis, which comes less than two years after strongman Hosni Mubarak was ousted by a popular revolt, has sparked fears of new violence in the Arab world's most populous state.
Dozens of Egyptians protested in the US capital Washington DC, as well as the states of Virginia and Maryland, on Tuesday against the president, calling for him to retract the declaration and refrain from using violence against peaceful protesters.
The protesters said Morsi's declaration was a real threat to Egypt's new democracy and pushing the country into an "ambiguous future." They also called on the United States to stop backing the ruling authority in light of the regime's moves to impose a stronghold on the state.