UNITED NATIONS — The U.N. Security Council expressed concern on Thursday at a political deterioration in Yemen threatening a transition to democracy in the Middle East state where year-long protests ended former president Ali Abdullah Saleh's 33-year rule.

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Saleh left office last month, handing power to Abd-Rabbu Mansour Hadi under the terms of an agreement crafted by his Gulf neighbors, with U.S. and U.N. backing, that envisions elections in 2014. The military is to be restructured in the meantime.

But the year of protests against Saleh and fighting among Yemeni factions have allowed al Qaeda's regional wing to seize swathes of south Yemen and Shi'ite Muslim Houthi rebels to carve out their own domain in the north.

"The Security Council expresses concern at the recent deterioration in cooperation among political actors and the risks this poses to the transition," the 15-nation panel said in a statement. "The Security Council expresses its strong concern about intensified terrorist attacks."

A split in the military has also led to fighting among rival units and threatened to tip into civil war.

The council also noted "with concern that children continue to be recruited and used by armed groups and certain elements of the military and calls for continued national efforts to discourage the use and recruitment of child soldiers."

It called upon political actors in Yemen to remain committed to the political transition, to constitutional order, and to play a constructive role and reject violence.

The United States and Saudi Arabia are keen for the Gulf transition plan to work, fearing that a power vacuum in Yemen is giving Islamist militants space to thrive alongside a key crude shipping strait in the Red Sea.

Saleh's son and nephew have control of key units armed for "counter-terrorism" by the United States, which was the target of an abortive bomb plot by the Yemeni branch of al Qaeda.

Many southerners complain that northerners have discriminated against them and usurped their resources. Most of Yemen's fast-declining oil reserves are in the south. The central government has denied there was any discrimination against the south.

Yemeni factions, including separatists who want to reinstate a southern state which united with the north in 1990, have been invited to a national dialogue ahead of a parliamentary poll.

The Security Council also urged all parties in Yemen to allow unimpeded safe access for humanitarian aid.

"The Security Council notes the formidable economic and social challenges confronting Yemen, which have left many Yemenis in acute need of humanitarian assistance," it said.