UNITED NATIONS - Yemen warned on Wednesday that if Iran does not allow a cargo ship bound for the Arabian Peninsula with a military escort to be searched, then Tehran "bears complete responsibility for any incident that arises from their attempt to enter Yemeni waters."
Iran said earlier on Wednesday it would not allow Saudi Arabia-led coalition forces to inspect the ship, which it says is carrying humanitarian aid. The ship left Iran on Monday under escort by Iranian warships.
Yemen's warning came in a letter, seen by Reuters, from its UN mission to the United Nations Security Council.
"The Yemeni government and the coalition forces do not object to aid shipments entering Yemen as long as they obtain the necessary permits from the legitimate government of Yemen and are searched prior to entry," the letter said.
Gulf Arab countries in the military coalition since March 26 have been bombing Houthi militia and allied army units that control much of Yemen, as well as inspecting ships entering Yemeni waters in a bid to stop weapons smuggling.
Saudi Arabia has accused Tehran of arming the Shi'ite Houthis, charges the Islamic Republic denies.
Saudi Arabia and its Sunni Muslim allies believe the Houthis are a proxy for their regional rival, Shi'ite Iran, in a power struggle that has helped exacerbate sectarian tensions across the Middle East.
On Tuesday, Iran complained to the Security Council that the Saudi-led coalition was hindering its attempts to send aid.
"The Islamic Republic of Iran has tried by all means to alleviate the suffering of the affected Yemeni people; efforts that have mostly been thwarted by the coalition forces," Iran's UN Ambassador Gholamali Khoshroo wrote to the Security Council in a letter, also seen by Reuters.
"Indeed, the destruction of the transportation infrastructure of Yemen by the coalition forces has adversely impacted the delivery of humanitarian assistance," he wrote.
A five-day truce that began on Tuesday to allow for the delivery of aid to Yemen appeared to be broadly holding. The United Nations says some 12 million people in the war-torn impoverished country need help.
UN aid chief Valerie Amos on Tuesday appealed for all aid for Yemen to be routed through the world body, which has a distribution hub in nearby Djibouti. Iran's state news agency IRNA said the vessel left on Monday for a Yemeni port held by Houthis.
"It is essential that humanitarian assistance is not politicized," Amos said in a statement.