Security Council members are discussing Yemen's request, Jamal Benomar told reporters Thursday after Security Council consultations on Yemen's political transition.
Yemen's Defense Ministry announced Wednesday that Yemeni authorities seized an Iranian ship last month carrying material for bombs and suicide belts, explosives, Katyusha rockets, surface-to-air missiles, rocket-propelled grenades and large amounts of ammunition.
Yemeni President Abed Rabbu Mansour Hadi sent a message to his Iranian counterpart, Mahmoud Ahmadinejad, last week calling on him to stop sending arms to Yemen and quit supporting a southern separatist movement, according to an official in the Yemeni president's office, who spoke Thursday on condition of anonymity because he was not authorized to brief the media.
Benomar would not say if the U.N. could confirm that the weapons were Iranian. He said it would be up to the U.N. investigation to determine "where the shipment came from, who the recipients were, etc."
Yemen recently has witnessed several cases of illegal arms shipments through its porous shores and also is home to an active branch of al-Qaida, which staged several failed or foiled attacks on U.
Yemen has been struggling with a transition to democracy since Arab Spring protests a year ago forced Ali Abdullah Saleh to step down after 33 years as president. Hadi leads a transitional government that is trying to promote national reconciliation, draft a new constitution and hold elections.
Saleh, who was allowed to remain in Yemen under the power-transfer deal, has been blamed by many over the past year for using loyalists and relatives in powerful posts to stall reform efforts.
Britain's U.N. Ambassador Mary Lyall Grant and Moroccan Ambassador Mohammed Loulichki, who led a recent Security Councill mission to Yemen, said Hadi and other government officials urged the council to impose strong measures against anyone trying to undermine the political transition.
The Security Council adopted a resolution in June that threatened non-military sanctions against those trying to interfere with Yemen's move to democracy.
Benomar said council members "heard in no uncertain terms during their recent visit to Yemen that acts of obstruction are impeding the transition" and that it was clear who those actors were. He gave no details and the Security Council did not indicate if any sanctions would be discussed.
Lyall Grant said Hadi told council members that the first phase of the transition involving the restructuring of the military and consolidating gains against al-Qaida was complete.
A national dialogue, a key feature of the second phase, will begin March 18 to lead up to elections in February 2014, Benomar said.
Lyall Grant painted a grim picture of impoverished Yemen: half of its 24 million people have no access to clean water and sanitation, 10 million don't have enough food and 1 million children suffer from acute malnutrition.
Benomar told the Security Council he lamented that very little of the nearly $8 billion that international donors have pledged has actually been received to help Yemen overcome its humanitarian crisis. He said "the governments need to accelerate the establishment of a mechanism to absorb the donor funded programs and the donors in turn need to fulfill their commitments."
"I told the council that the ball is in their court. They will need to act now. There is no time for complacency. Time is running out and there will be no second chances," Benomar said. "Yemenis need their support now."
Associated Press writer Edith M. Lederer contributed to this report.