Shi'ite Muslim rebels in Yemen are giving President Abed Rabbu Mansour Hadi 10 days to form a new government or face another possible takeover.
The rebels, known as Houthis, issued their ultimatum Friday, warning the president that "all revolutionary options are open" if a new government is not in place.
Hadi has appointed Khaled Bahah as the new prime minister, but squabbling among the Houthis and other political parties that have been promised Cabinet seats and ministerial posts have held up a new administration.
A power-sharing government is part of a United Nations-brokered deal to end Yemen's political crisis that saw the Houthis seize control of the capital in September after weeks of violence.
They promise to withdraw their forces from Sanaa when a new government is in place.
A State Department spokesperson said all Yemenis, including the Houthis, have an important role to play in working peacefully to form a government that can meet the needs of the Yemeni people and continue to pursue the key steps of its political transition.