The United States raised concerns Sunday with Yemen's president that members of the former government were disrupting the country's political transition, the White House said.
John Brennan, President Barack Obama's assistant for homeland security and counter-terrorism, called President Abdrabuh Mansur Hadi to discussion the situation.
It came at end of a week that saw cabinet members loyal to ex-president Ali Abdullah Saleh walk out of a cabinet meeting in what the opposition portrayed as an attempt to bring down the unity government.
Brennan told Hadi "it is essential that all Yemeni political actors, especially those from the previous government, play a constructive role in the transition process, and he expressed concern over recent reports that some former government officials are being disruptive," the White House said in a statement.
The 34-member unity cabinet was appointed in December under a hard-won transition deal, in which Saleh gave up the presidency after 33 years in power.
Saleh was the fourth Arab leader to fall since the beginning of the Arab Spring revolutions.
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Saleh retains the leadership of the General People's Congress, however.
Yemen's local Al-Qaeda branch, the self-proclaimed Partisans of Sharia (Islamic law), exploited the decline in central government control that accompanied anti-Saleh protests that began last January and eventually forced him to cede power.
During the unrest, the militants seized large swathes of southern and eastern Yemen.
The White House said Brennan commended Hadi's leadership and the two men pledged that their countries would work together to confront Yemen's security and economic challenges.
"President Hadi thanked the United States for its strong support and affirmed his commitment to restore stability to Yemen through a political transition," it said.
The top US diplomat for the Middle East was headed to Sanaa on Sunday to meet senior government officials and activists.
Assistant Secretary of State for Near Eastern Affairs Jeffrey Feltman will "highlight the US commitment to Yemen's political transition as well as the need for the transition process to allow broad participation by the Yemeni people," the State Department said Saturday.