YEMEN/JORDAN (REUTERS) - A small sign of relief for those caught up in Yemen's civil war.

On Saturday (Nov 26) an aircraft carrying 1.9 million doses of vaccines was delivered to Sanaa's airport.

The vaccines, which are expected to reach 600,000 children, aim at immunising children against diseases including diphtheria, tuberculosis and meningitis. But Unicef says many supplies are yet to reach the children, and there are not enough to go around.

Unicef regional director for the Middle East, Geert Cappelaere, said: "It is a very tiny step, it may sound huge - 1.9 million doses of vaccine, but there are many more millions of vaccines needed, if we want to prevent that there will be a break in the routine immunisation in the country, there are many more supplies needed."

Tension has been fierce since the Saudi-led coalition intervened in the war between forces loyal to President Hadi and the Houthis in 2015.

Since then ground fighting and air strikes have killed over 8,000 people, according to UN figures.

Saudi Arabia says the Houthi rebels are backed by Iran, its regional rival, something Iran denies.

Saudi Arabia blocked all see and land routes into the country after the rebels fired a missile aimed at Riyadh.

Under international pressure, the blocked was lifted, allowing vital aid into a country on the brink of starvation.

More than 20 million people are in need of urgent humanitarian aid.