It has also "emboldened Maoist insurgents and widened division between political parties and the King," US State Department spokesman Adam Ereli said in a statement.
The US remains particularly concerned by the Maoist insurgency, which presents the most immediate threat to a peaceful and prosperous Nepal, he said. "We urge the King to return to democracy by initiating a dialogue with the country's political parties," he said.
"After one year of unsuccessful authoritarian rule, this is the best way to address the Maoist insurgency and to build a brighter future of Nepal's people," the statement said.