UNITED NATIONS - The UN Security Council failed Friday to back a Russian appeal for an immediate ceasefire or humanitarian pauses in war-torn Yemen, where critical fuel shortages threatened relief efforts and doctors described desperate scenes.

Russia requested an urgent meeting of the 15-member council as the Saudi-led air war on Yemen's Huthi rebels entered a sixth week, crippling deliveries of fuel, food and medicine.

The latest strikes and clashes on the ground killed 47 people in the second city of Aden, where the Red Cross scrambled to evacuate staff and patients from a hospital when it became a front line.

UN Secretary-General Ban Ki-moon has warned that fuel shortages could bring all relief operations to a halt "within days," echoing alarm from the International Red Cross and other embattled aid agencies.

During a closed-door council meeting, Russia proposed a draft statement calling for an immediate ceasefire or at least humanitarian pauses, and an urgent return to political negotiations.

But after the statement failed to win endorsement, Ambassador Vitaly Churkin said fellow envoys were showing "amazing indecision" in the face of the worsening humanitarian crisis in Yemen.

Russia's diplomacy has been greeted with some suspicion given Moscow's close ties to Iran, which is supporting the Huthi rebels, who have seized the capital Sanaa and forced Yemen's president into exile. (AFP)