Saudi fighter jets launched three "aerial attacks" on the ships which were bound for the northwestern Yemeni province of Sa’ada, Iranian news agency IRIB quoted Yemeni TV channel al-Masirah as saying.
In its latest report released on Sunday, UNICEF detailed the delivery of aid to the Yemeni people during a five-day humanitarian ceasefire which went into effect on May 12 and ended earlier in the day at 2000 GMT.
“During the pause, UNICEF was able to deliver assistance to affected people across the country, however humanitarian assistance cannot replace the needs of 26 million people who have been cut off from a regular supply of commercial imports of food and fuel,” said Julien Harneis, the UNICEF representative for Yemen.
“Hundreds of adults and children have already died during this conflict, many of whom could have been saved had we got supplies to them on time. We need to do everything we can to prevent any more of these unnecessary deaths,” he went on to say.
Following the termination of the ceasefire, Riyadh resumed airstrikes against the Yemeni people, hitting several positions in the southern port city of Aden.
The Saudi strikes on UNICEF vessels came as an Iranian ship, with tons of much-needed aid, including food and medical supplies, is now heading towards the Yemeni port city of Hudaidah.
The Riyadh regime has already blocked earlier Iranian aid deliveries to Yemen. Last month, it prevented two Iranian civilian planes from delivering medical aid and foodstuff to the Yemeni people, Press TV reported.
On Saturday, Johannes van der Klaauw, the UN humanitarian coordinator for Yemen, said Saudi Arabia's harsh inspection process is obstructing the flow of humanitarian aid into war-wracked Yemen.
"The arms embargo and its inspection regime results in commercial goods, be it by air or by ship, no longer reaching the country,” he pointed out.
Saudi Arabia started military aggression against Yemen on March 26 - without a UN mandate - in a bid to undermine the Houthi Ansarullah movement, which currently controls the capital, Sana’a, and other major provinces, and to restore power to Yemen’s fugitive former President Abd Rabbuh Mansour Hadi, who is a staunch ally of Riyadh.
According to Yemen's Freedom House Foundation, the Saudi airstrikes have claimed the lives of 3,979 Yemeni people so far while more than 6,887 others have been wounded.