The aid group Doctors Without Borders has airlifted medical supplies to Yemen's rebel-held capital, Sana'a, as fighting continues there and in the southern port city of Aden.
The medical aid group said a cargo plane carrying 15 tons of supplies landed in the capital Monday. It also said it was working to establish additional supply routes by sea to Aden.
"Getting aid into the country is only part of the challenge," said Marie-Elisabeth Ingres, head of the group's mission in Yemen. "Due to the fighting and insecurity within Yemen, we are also facing difficulties assessing the needs and deploying staff and supplies to the areas where the needs are greatest."
Airstrikes continue in Aden
Also Monday, the Saudi-led coalition continued its airstrikes against Houthi rebels in Aden.
A coalition spokesman, Brigadier General Ahmed Asseri, said coalition military forces targeted a sports stadium.
"The situation has become critical and we must not let these militias take advantage of these facilities,” Asseri said. “They are using the stadiums and schools as military storage, so we must not give them a chance to take advantage of them to reorganize their operations."
The Iran-backed Houthis are battling forces loyal to Yemen's internationally backed president, Abd-Rabbu Mansour Hadi, who recently fled Yemen for Saudi Arabia.
More than 600 people have been killed in the fighting and 100,000 residents were forced to flee their homes.