UN aid chief calls for ceasefire in Yemen

The UN's humanitarian affairs chief called Tuesday for a ceasefire in Yemen's ongoing conflict to facilitate the flow of direly needed international assistance.

"All parties must live up to their obligations under international humanitarian law. I ask that the parties implement a cessation of hostilities, not least in and around all the infrastructure and facilities on which the aid operation and commercial importers rely," Mark Lowcock said in a statement.

Lowcock made particular mention of the Yemeni port city of al-Hudaydah, where he said the UN stands ready "to play an enhanced role in ensuring the appropriate use of key facilities."

Last week forces loyal to Yemen's internationally-recognized government launched a fresh military operation to retake al-Hudaydah -- and its two strategic seaports -- from Houthi rebels.

Already the Arab world's poorest nation prior to the start of the conflict, Yemen has remained wracked by violence since 2014 when the Houthis overran much of the country, including the capital, Sanaa.

The conflict escalated in 2015 when Saudi Arabia and its Arab allies launched a devastating air campaign in Yemen aimed at rolling back Houthi gains.