The United States hit Yemen's former president Ali Abdullah Saleh and two Huthi rebel commanders with sanctions Monday, two days after Saleh walked out on the new government.
The US Treasury said it was blacklisting Saleh, Abdullah Yahya al-Hakim and Abd al-Khaliq al-Huthi "for engaging in acts that directly or indirectly threaten the peace, security, or stability of Yemen."
The US action followed Saturday's UN Security Council sanctions on the three men, for threatening peace in the impoverished Arab country.
The UN sanctions prompted Saleh to pull his General People's Congress party out of the just-formed unity cabinet, plunging the country back into political crisis after months of attempts to foster a peace deal between Saleh, the Huthi insurgents believed allied to him, and their political rivals.
The Treasury said the three men "have, using violence and other means, undermined the political process in Yemen and obstructed the implementation of its political transition, outlined by the agreement of November 23, 2011... which provides for a peaceful transition of power in Yemen."
The sanctions freeze any assets the three might have in US jurisdictions and forbids Americans from doing business with them.
Saleh was the turbulent country's president from 1990 to 2012 before he was forced to step down following nationwide protests.
The US Treasury said that since then he has "reportedly become one of the primary supporters of violence perpetrated by individuals affiliated with the Huthi group."
Hakim, the Treasury said, was implicated in plotting a coup attempt against Yemen President Abdrabuh Mansur Hadi as the Huthi forces sought to take over Sanaa, Yemen's capital.
The Treasury added that Hakim remained in Sanaa in September "to organize military operations so as to be able to topple the Yemeni government" if peace efforts failed.
Rebel commander Al-Huthi was behind several attacks and attempted attacks on the Yemen government and foreign diplomatic facilities over the past year, the Treasury said.