A top aide to U.S. President Barack Obama on Sunday met with Yemeni President Ali Abdullah Saleh and urged him to "fulfill expeditiously" his pledge to sign a deal for peaceful transition in his country, the White House said.

John Brennan, Obama's assistant for counterterrorism and homeland security, met with Saleh in Riyadh, capital of Saudi Arabia, where the Yemeni president is recuperating from injuries sustained during an attack on his presidential palace in early June.

"During the meeting, Mr. Brennan called upon President Saleh to fulfill expeditiously his pledge to sign the GCC-brokered agreement for peaceful and constitutional political transition in Yemen," the White House said in a statement.

Brennan "emphasized the importance of resolving the political crisis in Sanaa so that the Yemeni government and people can successfully confront the serious challenges they face, including the terrorist attacks carried out by al-Qaeda in the Arabian Peninsula, which have claimed the lives of hundreds of Yemeni citizens," the White House added.

Despite anti-government protests since mid-February calling for his ouster, Saleh has broken promise three times to sign the deal brokered by the Gulf Cooperation Council, under which he should step down in return for immunity from prosecution. The U.S. fears that the Yemen-based al-Qaeda in the Arabian Peninsula, which has been trying to bomb targets on U.S. soil, is taking advantage of the turmoil in the poor Arab country.

Brennan told Saleh that "the United States is working closely with Yemen's friends and supporters in the Gulf Cooperation Council, Europe and elsewhere to ensure that much needed assistance will flow to Yemen as soon as the GCC proposal is signed and implemented," adding that the U.S. believes that a transition in Yemen should begin immediately so that the Yemeni people can realize their aspirations.

The White House said that Brennan also reiterated the U.S. government's condemnation of the attack against Saleh and other Yemeni officials, and wished him a "speedy" recovery.

Saleh said that the GCC deal and a UN conciliation proposal are the strong ground for resolving Yemen's political impasse.