Yemen asks UN to back foreign ground force to battle Houthis
Yemen's government has urged the UN to authorise the deployment of foreign ground forces to drive back Houthi rebels, specifically in Aden and Taiz.
Rebel fighters have been advancing in both cities despite six weeks of air strikes by a Saudi-led coalition.
The strikes began after the government sent the UN a similar letter requesting military help from Gulf Arab states.
The government also called on Tuesday for human rights groups to document "barbaric violations" by the rebels.
The letter, from Yemen's permanent representative to the UN Khaled Alyemany, cited an incident on Wednesday when at least 32 people were killed while trying to flee fierce fighting in Aden in a boat. Witnesses and medics said the boat was hit by rebel shellfire.
The letter said Houthis were "targeting anything that moves" in Aden.
"We urge the international community to quickly intervene by land forces to save Yemen, especially Aden and Taiz," it said.
Fighting has been particularly fierce in Aden's al-Tawahi district where rebels have been battling pro-government forces for control.
The international community has expressed growing concern for civilians trapped in the fighting.
More than 20 international aid agencies have warned fuel shortages in Yemen could halt their work.
The Saudi-led coalition aims to restore the government of exiled President Abdrabbuh Mansour Hadi .
The president fled the capital Sanaa in February and took refuge in Aden. When the Houthis reached the outskirts of Aden at the end of March, he left the country for Saudi Arabia.
Since then, more than 640 civilians have been killed, according to the UN.
US Secretary of State John Kerry called for a pause in the fighting when he arrived in the Saudi capital Riyadh on Wednesday.
Speaking earlier in Djibouti, he said he would raise the issue of a temporary halt to air strikes with Saudi officials.
"We are deeply concerned about the humanitarian situation that is unfolding in Yemen - shortages of food, shortages of fuel, shortages of medicine. The situation is getting more dire by the day," he said.
A joint statement by 22 aid agencies had earlier dismissed Mr Kerry's call for a "humanitarian pause" and called for an immediate end to the conflict.
They also warned that their work risked coming to an abrupt end within a week unless land, sea and air routes to Yemen were opened for the importation of fuel.